单项选择题

有如下程序:
#include<iostream>
using namespace std;
class Base
public:
void fun()cout<<"Base::fun"<<endl;
;
class Derived:public Base
public:
void fun()
______
cout<<"Derived::fun"<<endl;

;
int main()
Derived d;
d.fun();
return 0;

已知其执行后的输出结果为:
Base::fun
Derived::fun
则程序中下画线处应填入的语句是______。

A.Base.fun();
B.Base::fun();
C.Base->fun();
D.fun();