有以下程序： #include ＜iostream＞ using namespace std; class Base public: Base() virtual void who() cout＜＜ Base Class ＜＜end1; ～Base() ; class Derivel : public Base public: void who() cout＜＜ Derivel Class ＜＜end1; ; class Derive2 : public Base public: void who () cout＜＜ Derive2 Class ＜＜end1; ; int main () Base *p; Derivel obj1; Derive2 obj2; p=&obj1; p=&obj2; p-＞who ( ); return 0; 执行程序后的输出结果是( )。
A．Base Class
B．Derivel Class
C．Derive2 Class
D．程序编译时出错