A、  B、  C、  C题目不是问句，而是叙述某一事实的陈述句，因此答案必须是与此相应的回答。题目说Carter先生最近好像很忙，(C)问为什么会这样，因此是最合适的答案。(A)和(B)的人称代词都与题目不符。

Should we complain to the manager?
(A) No, let’s just wait for a bit.
(B) He’ll manage it very soon.
(C) We should certainly find it out.

Mr. Carter seems so busy lately.
(A) It was delivered late.
(B) It seems quite big for him.
(C) Why is that?