单项选择题

有如下程序:
#include <iostream>
using namespace std;
class AA
public:
virtual void f()

cout<< "AA";

;
class BB : public AA
public:
BB()

cout << "BB";

;
class CC : public BB
public:
virtual void f()

BB::f();
cout << "CC";

;
int main ()
AA aa,*p; BB bb; CC cc;
p=&cc;
p->f ();
return 0;
执行上面的程序将输出( )。

A.AA
B.AABBCC
C.BBAABBCC
D.BBBBAACC