I have no idea ____ the journalist could have got his information from

题目

I have no idea ____ the journalist could have got his information from
A.that
B.what
C.which
D.where
为什么答案是D
from后面不是缺少宾语吗?不应该用which吗?

答案

定语从句中which做关系代词,指代物,可以在从句中作主语、宾语
但是这个句子是同位语从句,which表示“哪个”有选择范围.
I have no idea which answer is correct
题目当中表示什么地方,因此用where