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( )。
A．Base
Base
B．Base
Derived
C．Derived
Base
D．Derived
Derived