——Must I take a bus?

题目

——Must I take a bus?
——No,you( ).You can walk there.
A.mustn't B.don't have to C.can't D.had better not

答案

选B
Must的否定回答 要么用NEEDN'T 要么用DON'T HAVE TO
两个的意思都是“不用”或“不必”
而MUSTN'T意思是“禁止做......”
故选B
That's all.