选C
“we have stayed”的stay后面没有介词,那么后面就不能接名词,只能接副词,所以that不能接,只能接where
因为从句还原应该是完整的,
先看A,假若还原就是
we have stayed that（却介词）
C中：
we have stayed where不用介词,where是副词
比如：
I have to go to school.
和
I have to go to there.