单项选择题

有以下程序:   #include<stdi0.h>   main( )   { FILE *fp; int i=20,j=50,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