有以下程序

#include <stdio.h>

main()

{ FILE *fp; int i;

char ch[]="abcd",t;

fp=fopen("abc.dat","wb+");

for(i=0; i<4; i++) fwrite(&ch[i],1,1,fp);

fseek(fp,-2L,SEEK_END);

fread(&t,1,1,fp);

fclose(fp);

printf("%c\n",t);

}

程序执行后的输出结果是

A)d

B)c

C)b

D)a