下列程序运行后的输出结果是( )。#include＜iostream.h＞void fun(int,int,int*);void main(){int x,y,z; fun(5,6,&x); fun(7,x,&y); fun(x,y,&z); cout＜＜x＜＜","＜＜y＜＜","＜＜z＜＜end1;}void fun(int a,int b,int *c){ b+=a;*c=b-a;}

A．5, 5, 5

B．6, 6, 6

C．5, 6, 7

D．7, 7, 7

常态足