The reason is _____ my bike was broken?A that B why C what D how 应选哪一个?直观是选B,为什么不选择A?怎么感觉A也对?

这是固定句型吧 the reason 就那几个句型 记住就ok啦

B the reason is why my bike was broken? 意思是： 这就是我自行车坏掉的原因吗？反问句。

选A
The reason is that my bike was broken 原因是当时我的自行车坏了。(用 that 引导表语从句的时候，that在从句中作引导词但没有词义，在逻辑上是合适的)
The reason is why my bike was broken 原因是当时我的自行车为什么坏了。(用why引导表语从句的时候，Why在从句中作了状语，但在逻辑上不合适)
权威例句中找不到The reason is why....的例句：
Part of the reason is that there aren't many liquid financial products suited to the task.
The reason is that advertised rates don't include taxes, fees, insurance and other extras.
The reason is that the break-up would apply only to the UK arm of PwC.

The reason is __why___ my bike was broken?
这就是为什么我的自行车坏了的原因。
有因有果。。前面The reason ......后面当然是为什么。

此题在这里应选B.个人分析下A和B的差别：
The reason is why my bike was broken.意思是：这就是我自行车坏的原因.（问题在于自行车本身,可能是哪个零件坏了,找到原因了）
The reason is that my bike was broken 意思是：原因是我的自行车坏了.（应该是要做什么事要用到自行车,因为自行车坏了,就不能去做了.或者别人要借,但你没接,就可以这么说）
之所以此题选B是因为有个问号,可能是找到车坏的原因了.再者,因为是单独拿出来的句子,如果你把这句放到某个文章里,句子末尾换成句号,那就不一定选A还是选B了,要根据文章的语境.个人观点,希望有用