is this the reason .

题目

is this the reason .
is this the reason --------- in the repourt for her success in the job?
A she explained B why she explained C how she explained

答案

A
A 此为定语从句.reason 是explain的宾语,引导词that可以省略.
B 定语从句若用why 引导,后边内容应该是事情结果.
按照4楼,则成为why引导表语从句.
C how 不能引导定语从句.但若去掉前边的 the reason,也可以选.