In C++, a function contained within a class is called

a member function
an operator
a class function
a method

The correct answer is A. A member function is a function that is contained within a class. It can access the private and protected members of the class.

B. An operator is a special symbol that performs an operation on operands. For example, the + operator adds two operands together.

C. A class function is a function that is not contained within a class. It cannot access the private and protected members of the class.

D. A method is a synonym for a member function.