—Can you tell me ________?

—About two months ago. [ ]

A. where my watch is

B. where is my watch

C. when you bought your camera

D. when did you buy your camera

在我国，房屋租赁行为合法有效的凭证是( )

A．房屋租赁合同

B．房屋租赁证

C．房屋租赁登记书

D．房屋产权证