The proposal had been put forward, and then arose the question ________ we were to get the proofs __

The proposal had been put forward, and then arose the question ________ we were to get the proofs ________.

A.what, needed

B.where, to need

C.what, to need

D.where, needed

答案及解析： D

question后面是个where引导的同位语从句，从句中缺少地点状语；needed过去分词作后置定语，“被需要的”．