$```$

class Foo

$\{$

bool operator$-($const Foo $8$otherFoo$)$ const;

Foo soperator$-($const Foo sotherFoo$)$;

$\}$:

int operator$[]($int index$)$ const;

$```$

The three member functions are all examples of what?Operator abstractionOperator overloadingOperator overridingOperator overdrivingOperator inheritance