This book be Carla's Her name is on the book

This book be Carla's Her name is on the book
1．This book ________ be Carla’s.Her name is on the book.
A．might B．could C．must D．can’t
2．Jack’s bike is blue,so this yellow one ________ be his.
A．mustn’t B．can’t C．couldn’t D．mightn’t
3．The guitar ________ belong to Alice.Only she plays the guitar here.
A．could B．must C．can’t D．can
4．—What do you think“upset”mean?—I’m not sure.It ________ mean sad,
A．must B．can C．might D．can’t
5．I’ll have a report ________ computer science next week.
A．at B．of C．on D．in
6．This backpack must be ________.I saw her carry it yesterday.
A．Lucys B．Lucy C．Lucys’ D．Lucy’s