That's all ______ I have seen and heard.

That's all ______ I have seen and heard.
A.which B.that C.where D.what
问为什么
The Oscar is one of the film prizes ______ offered to any Chinese actor or actress so far.
A.which are not B.that have not been C.that has not D.that has not been
请讲讲这句话里的单复数关系