英语从句提问=_|||________ this material can be used in our factory has not been studied.A.Which B.What C.That D.Whether我选了B请大人分析

英语从句提问=_|||________ this material can be used in our factory has not been studied.A.Which B.What C.That D.Whether我选了B请大人分析
英语从句提问=_|||
________ this material can be used in our factory has not been studied.
A.Which B.What C.That D.Whether
我选了B
请大人分析

英语从句提问=_|||________ this material can be used in our factory has not been studied.A.Which B.What C.That D.Whether我选了B请大人分析
这种材料是否能被工厂使用,还正处在研究之中.
这句话不是名词性从句,不需要用what,如果用what,句子意思解释不通.
用“wherther”,“是否”