单项选择题

请选出以下程序的输出结果 ______。#include <stdio. h>sub(x, y, z)int x, y,*z;{*z=y-x:}main(){ int a, b, c; sub 10,5,&a);sub(7,a,&b);sub(a, b, &c); printf("%d,% d,/%d\n", a, b, c);}

A.5,2,3
B.-5,-12,-7
C.-5,-12,-17
D.5,-2,-7