Find the answer __ the question,please.A of B with C to D for 请大家_英语解答

Find the answer __ the question,please.
A of B with C to D for 请大家帮我解答并说明原因,一定要说明原因啊!

人气：206 ℃　时间：2019-10-11 18:01:29

解答

C
answer to the question问题的答案
问我为什么,我只能说,书上这样写的,惯用吧