All _____ we need is enough rest after long hours' work. A. the thing B. that C. what D. which

B. that是对的.首先理清句子的结构,主句为All is enough rest ...,而（that）we need是定语从句,修饰all的,that是关系代词,在定语从句里做宾语,故还可以省去.all the thing的话,thing要用复数things,而且后面的谓...