---Must I finish the exercise this afternoon?

---Yes, you ________, but you ________ finish it now．

1. A.
   must…mustn't
2. B.
   must…don't have to
3. C.
   may…needn't
4. D.
   may…mustn't

—Must I finish the exercise this afternoon?
—Yes, you ______, but you ______ finish it now.

—Yes, you ________, but ________ finish it now. (　)

A．must ; mustn't

B．must; don't have to

C．may; needn't

D．may; mustn't