单项选择题

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