#include <stdio.h>
main（）
{ FILE *fp; int i=20,j=30,k,n;
fp=fopen（"d1.dat","w"）；
fprintf（fp,"%d＼n",i）;fprintf（fp,"%d＼n",j）;
fclose（fp）;
fp=fopen（"d1.dat","r"）;
fscanf（fp,"%d%d"，&k,&n）; printf（"%d %d＼n",k,n）;
fclose（fp）;
}
程序运行后的输出结果是
A．20 30
B．20 50
C．30 50
D．30 20