拜托大家帮解决一下这些定语从句选择（不用解释,

拜托大家帮解决一下这些定语从句选择（不用解释,
1.The two things ____they felt very proud are Jim·s gold watch and Della·s hair.(·为一撇)
A.about which B.of which C.in which D.for which
2.Do you know which hotel____?
A.she is staying B.she is staying in C.is she staying
D.is she staying in
3.There is only one thing____I can do.
A.what B.that C.all D.which
4.Who can think of situation______this idiom can be used?
A.which B.that C.where D.in that