Is there any special reason ______ you want me to wear my new su

Is there any special reason ______ you want me to wear my new suit to the party?
A、how
B、what
C、why
D、which
【正确答案】：C
【题目解析】：译文：你想让我穿新西服去聚会有什么特别的理由吗？本题考查定语从句。当the reason为先行词时，关系副词常用why或者省略why不写。答案为C。