有如下程序：#includeusing namespace std;class B{public;virtual void f() {cout<<"B";}void g(){cout<<"B";}}class D;public B {public; void f(){cout<<"D";} void g(){coun<<"D";} }void h(B*p){p->f();p->g();}int main(){ D obj; h(&obj);return 0;}运行这个程序的输出结果是：

A．DD

B．BB

C．BD

D．DB