------I think we should buy a car now so that it will be convenient for us.

------      , but do you think we have so much money?

A．You are dead right

B．You are joking

C．I don’t believe it

D．Come off it

A住宅小区的住宅建筑基底总面积是1万m²，而该小区的住宅用地面积是5万m²，该小区的住宅建筑净密度是25%。( )