I don't believe what you have told us is true,_______A is it B have you填哪个

I don't believe what you have told us is true,_______
A is it B have you
填哪个

A 这是个宾语从句的否定前移句子（其实还是否定从句,翻译：我相信……不……）,其中从句的主语为what you have told,构成反义疑问句时,用it 进行替代,即属于“前否后肯”型,所以正确答案为is it.

A，反义疑问动词要看后面的从句，从句的谓语动词是is

B啊！

B have you

选A，不解释

选A what you have told 是主语，is才是谓语，不关主句的事