There is no rule __________ has some exceptions.

There is no rule __________ has some exceptions.
A、that
B、but
C、which
D、what
【正确答案】：B
【题目解析】：此处but 为关系代词,引导定语从句,意思相当于that not/which not/who not这种用法非常特殊。这个句子可以改写成“There is no rule that has no exception.