单项选择题

有以下程序:
#include<iostream. h>
void fun(int a, int b, int c)
{a=456, b=567, c=678;}
void main()
{
int x=10, y=20, z=30;
fun(x, y, z);
cout<<x<<","<<y<<","<<z<<endl;
}
输出结果是______。

A.30,20,10
B.10,20,30
C.456,567,678
D.678,567,456