单项选择题

有如下类声明: class Base{ protected: int amount; public: Base(int n=0):araount(n){ } int getAmount( )const{retum amount;} }; class Derived:public Base{ protected; int value; public: Derived(int m,int n):value(n1),Base(n){ } int getData( )const{return value+amount;} }; 已知x是一个Derived对象,则下列表达式中正确的是

A.x.value+x.getAmount( )
B.x.getData( )-x.getAmount( )
C.x.getData( )-x.amount
D.x.value+x.amount