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 tim()

____________
cout＜＜"Derived:: fun"＜＜endl;

;
int main()

Derived d;
d.fun();
return O;

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