一道单项选择英语题~~~~~~~~~

问题描述:

一道单项选择英语题~~~~~~~~~
---Mom,I want to play football.
---NO,you ____stop unlessyou finish your homeworkfrist.
A.don't have to
B.mustn't
C.not have to
D.have to not
选哪个?

选Bnot...unless是固定搭配,意思是直到...才...
而本身这个句子又有比较严厉的口气,说以用情态动词must