状语从句能用介词加疑问词吗?

题目

状语从句能用介词加疑问词吗?
例题：This kind of plant can grow best _____ it is warm and rains often.
A.in the place B.where C.in which
为什么?

答案

where 引导的地点状语从句 where 的确等于in which,但是前提条件是在“定语从句”的条件下!如果这句活改成：this kind of plant can grow best in the place in which (where) it is warm and rains often.这样就是...