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