单项选择题
有如下类声明: class Base{ protected; int amount; public; Base(int n=0):amount(n){} int getAmount()const{return amount;} }; class。Derived:public Base{ protected; int value; public; Derived(int m,int n):value(m).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.gctAmount()
C.x.getData().x.amount
D.X.value+x.amount