xdf section 4-18

   The record of the past is always incomplete, and the historian who writes about it inevitably reflects the preoccupations of their own time.

(A) the historian who writes about it inevitably reflects

(B) the historian writing about it will inevitably reflect

(C) a historian writing about it inevitably reflects

(D) writing about it, it is inevitable for historians to reflect

(E) historians in writing about it inevitably reflect

答案 是 e

答案里为什么有那个in呢？ 谢谢拉

那没有in不行么 

c为什么不对呢？