The line:
Virtual double earnings) const = 0;
Appears in a class definition. You cannot deduce that:
A) All classes that directly inherit from this class will override this method.
B) This class is an abstract class.
C) Any concrete class derived from this class will have an earnings function.
D) This class will probably be used as a base class for other classes.

Question

Quizplus · Accepted Answer

A pure virtual function (indicated by '= 0') makes the class abstract, meaning it cannot be instantiated and is intended to be a base class. However, derived classes are not required to override the pure virtual function unless they are concrete classes.

The Line: Virtual Double Earnings) Const = 0;