24 real OOP questions from the C# bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Inheritance?
Junior
A.the mechanism by which a derived type acquires the members of a base type, enabling reuse and an is-a relationship
B.a reference type defining a contract of members with no instance state, which a class or struct can implement, and a type may implement many of them
C.a class marked so that no other type may derive from it, preventing further extension of the hierarchy
D.the keyword applied in a derived class to replace a base member's implementation while preserving polymorphic dispatch through a base reference
A.Inheritance — the mechanism by which a derived type acquires the members of a base type, enabling reuse and an is-a relationship
B.Inheritance — a class that cannot be instantiated directly and may declare members without implementation that derived classes must complete
C.Inheritance — a member that exposes a getter and/or setter accessor to read or write a value, syntactically used like a field but backed by methods
D.Inheritance — a reference type defining a contract of members with no instance state, which a class or struct can implement, and a type may implement many of them
A.a base-class method explicitly marked to permit a derived class to supply a replacement implementation that is selected at run time
B.a reference type defining a contract of members with no instance state, which a class or struct can implement, and a type may implement many of them
C.a class that cannot be instantiated directly and may declare members without implementation that derived classes must complete
D.redeclaring an inherited member with the new modifier so the derived version shadows rather than polymorphically replaces the base version, dispatch depending on the static reference type
5. Which term means: "a reference type defining a contract of members with no instance state, which a class or struct can implement, and a type may implement many of them"?
A.Interface — the mechanism by which a derived type acquires the members of a base type, enabling reuse and an is-a relationship
B.Interface — redeclaring an inherited member with the new modifier so the derived version shadows rather than polymorphically replaces the base version, dispatch depending on the static reference type
C.Interface — a reference type defining a contract of members with no instance state, which a class or struct can implement, and a type may implement many of them
D.Interface — the keyword applied in a derived class to replace a base member's implementation while preserving polymorphic dispatch through a base reference
A.redeclaring an inherited member with the new modifier so the derived version shadows rather than polymorphically replaces the base version, dispatch depending on the static reference type
B.a class that cannot be instantiated directly and may declare members without implementation that derived classes must complete
C.a class marked so that no other type may derive from it, preventing further extension of the hierarchy
D.a member that exposes a getter and/or setter accessor to read or write a value, syntactically used like a field but backed by methods
A.Abstract class — the keyword applied in a derived class to replace a base member's implementation while preserving polymorphic dispatch through a base reference
B.Abstract class — redeclaring an inherited member with the new modifier so the derived version shadows rather than polymorphically replaces the base version, dispatch depending on the static reference type
C.Abstract class — a class marked so that no other type may derive from it, preventing further extension of the hierarchy
D.Abstract class — a class that cannot be instantiated directly and may declare members without implementation that derived classes must complete
A.Sealed class — a base-class method explicitly marked to permit a derived class to supply a replacement implementation that is selected at run time
B.Sealed class — a class marked so that no other type may derive from it, preventing further extension of the hierarchy
C.Sealed class — the keyword applied in a derived class to replace a base member's implementation while preserving polymorphic dispatch through a base reference
D.Sealed class — the mechanism by which a derived type acquires the members of a base type, enabling reuse and an is-a relationship
14. Which term means: "a base-class method explicitly marked to permit a derived class to supply a replacement implementation that is selected at run time"?
A.Virtual method — a member that exposes a getter and/or setter accessor to read or write a value, syntactically used like a field but backed by methods
B.Virtual method — a base-class method explicitly marked to permit a derived class to supply a replacement implementation that is selected at run time
C.Virtual method — a class that cannot be instantiated directly and may declare members without implementation that derived classes must complete
D.Virtual method — redeclaring an inherited member with the new modifier so the derived version shadows rather than polymorphically replaces the base version, dispatch depending on the static reference type
17. Which term means: "the keyword applied in a derived class to replace a base member's implementation while preserving polymorphic dispatch through a base reference"?
A.Override — a base-class method explicitly marked to permit a derived class to supply a replacement implementation that is selected at run time
B.Override — the keyword applied in a derived class to replace a base member's implementation while preserving polymorphic dispatch through a base reference
C.Override — the mechanism by which a derived type acquires the members of a base type, enabling reuse and an is-a relationship
D.Override — a class marked so that no other type may derive from it, preventing further extension of the hierarchy
A.a reference type defining a contract of members with no instance state, which a class or struct can implement, and a type may implement many of them
B.redeclaring an inherited member with the new modifier so the derived version shadows rather than polymorphically replaces the base version, dispatch depending on the static reference type
C.a class marked so that no other type may derive from it, preventing further extension of the hierarchy
D.the keyword applied in a derived class to replace a base member's implementation while preserving polymorphic dispatch through a base reference
20. Which term means: "redeclaring an inherited member with the new modifier so the derived version shadows rather than polymorphically replaces the base version, dispatch depending on the static reference type"?
A.Method hiding — a reference type defining a contract of members with no instance state, which a class or struct can implement, and a type may implement many of them
B.Method hiding — a class that cannot be instantiated directly and may declare members without implementation that derived classes must complete
C.Method hiding — redeclaring an inherited member with the new modifier so the derived version shadows rather than polymorphically replaces the base version, dispatch depending on the static reference type
D.Method hiding — a member that exposes a getter and/or setter accessor to read or write a value, syntactically used like a field but backed by methods
A.a member that exposes a getter and/or setter accessor to read or write a value, syntactically used like a field but backed by methods
B.the keyword applied in a derived class to replace a base member's implementation while preserving polymorphic dispatch through a base reference
C.redeclaring an inherited member with the new modifier so the derived version shadows rather than polymorphically replaces the base version, dispatch depending on the static reference type
D.the mechanism by which a derived type acquires the members of a base type, enabling reuse and an is-a relationship
23. Which term means: "a member that exposes a getter and/or setter accessor to read or write a value, syntactically used like a field but backed by methods"?
A.Property — a reference type defining a contract of members with no instance state, which a class or struct can implement, and a type may implement many of them
B.Property — the keyword applied in a derived class to replace a base member's implementation while preserving polymorphic dispatch through a base reference
C.Property — a class that cannot be instantiated directly and may declare members without implementation that derived classes must complete
D.Property — a member that exposes a getter and/or setter accessor to read or write a value, syntactically used like a field but backed by methods
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