单选题 有如下程序：
#include ＜iostream＞
using namespace std;
class Base
{
public:
void fun1(){ cout＜＜"Base/n";}
virtual void fun2(){ cout＜＜"Base/n";}
};
class Derived: public Base
{
public:
void fun1(){ cout＜＜"Derived/n";}
void fun2(){ cout＜＜"Derived/n";}
};
void f(Base&b) {b.fun1(); b.fun2();}
int main()
{
Derived obj;
f(obj);
return 0;
}
执行这个程序的输出结果是 ____ 。