— Do you think I should join the singing group, Mary?
— If I were in your shoes, I certainly would.
A. None of your business.
B. It depends.
C. Why not?
D. I don't think so.
网友回答
A. None of your business.
B. It depends.
(答案→)C. Why not?
D. I don't think so.
解析：考查交际用语。根据回答可知：第二个人赞成他加入这个唱歌团体，故用why not，为什么不呢？