The children had played the whole day long were worn out.A. all of whatB. all of whichC

问题补充：

The children, had played the whole day long, were worn out.

A. all of what

B. all of which

C. all of them

D. all of whom

答案：

A. all of what

B. all of which

C. all of them

(答案→)D. all of whom

解析：考查定语从句。句义：那些孩子们，所有人都玩了一整天，都累了。本题先行词是人（the children），且前面有介词，所以选择whom