单项选择题

下面程序的运行结果是  # include <iostream.h>  void fun(int * a,int * b)  {    int x= * a;    * a= * b; * b=X;    cout << * a << * b<<" " ;  }  void main( )  {    int x=1, y=2;    fun (& x,& y);    cout < < X << y << endl;  }

A.12 12
B.12 21
C.21 12
D.21 21