A、  B、  C、  B句子是询问谁关掉了办公室的灯的Who疑问句。

Why did you decide to go to graduate school?
(A)The semester starts in the fall.
(B)I reside in Southern California.
(C)It will help my career.

Who turned off the lights in the office?
(A)I’ll make sure and do it.
(B)I thought you did.
(C)It will be left on your desk.