-Must I do my homework now, Mum?

-_______. You can do it tomorrow.

 [      ]

A. No, you needn't

B. No, you mustn't

C. Yes, you need

D. Yes, you must

虽然社会保障事业惠及每一位社会成员，但每个人对保障的需求程度和保障对每个人产生的效用不同。 ( )