单选题 以下程序的运行结果是()#include "stdio.h"int main(){FILE *fp;int a=3,b=2,c=1,x,y,z;fp=fopen("d:\\data.txt","w");fprintf(fp,"%d,%d,%d",a,b,c);fclose(fp);fp=fopen("d:\\data.txt","r");fscanf(fp,"%d,%d",&x,&y);fclose(fp);z=3*x-y;printf("%d\n",z);getch();return 0;}