Correct Answer (Detailed Explanation is Below)
B.
In structures, members are public by default whereas in classes, they are private by default
Detailed Explanation
Answer: (B) In structures, members are public by default whereas in classes, they are private by default
The main difference between a struct and a class in C++ is their default access level.
In a struct, members are public by default. Therefore, they can normally be accessed directly from outside the structure.
In a class, members are private by default. Therefore, they cannot normally be accessed directly from outside the class.
Both structures and classes can contain data members, member functions, constructors, private members, public members, and other C++ features. The important difference asked here is the default access specifier.