单项选择题
A.fp=fopen("my.dat","r");B.fp=fopen("my.dat","r+");C.fp=fopen("my.dat","rb");D.fp=fopen("my.dat","rb+");
A.fscanf(fp,"%d%d",&a ,&b);B.fscanf(fp,"%d%d",a ,b);C.fscanf("%d%d",&a ,&b,fp);D.fprintf(fp,"%d",a ,b);
A.fclose(fp);B.close(fp);C.fclose();D.close();