i think it must be in your room,____?

问题描述:

i think it must be in your room,____?
A isn't it
B mustn't it
C needn't it
D wasn't it

A
must表猜测,must be用be
I think/believe 看的是宾语从句中的谓语
he/she thinks/believes 看的是主句的谓语
所以A