单项选择题

有以下程序
#include<stdio.h>
main() {
FILE *fp;
int k,n,a[6]={1,2,3,4,5,6};
fp=fopen("d2.dat","w");
fprintf(fp,"%d%d%d\n",a[0],a[1],a[2]);
fprintf(fp,"%d%d%d\n",a[3],a[4],a[5]);
fclose(fp);
fp=fopen("d2.daf","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.1 2
B.1 4
C.123 4
D.123 456