This question is incomplete. I've found the complete question online. It is the following:
5. Change the sentences below using must, can’t and might\may, whichever is correct.
For example: perhaps he was tired.
He may have been tired.
a) I am sure he isn’t from Cyprus.
b) Perhaps he was reading.
c) Perhaps Devkota wrote that poem.
d) Obviously, she passed the entrance.
Answer:
a) He can't be from Cyprus.
b) He might have been reading.
c) Devkota may have written that poem.
d) She must have passed the exam.
Explanation:
The options are the following:
must - indicates an obligation or a conclusion we reach with a high degree of certainty. For instance: James is never late. Something must have happened, otherwise he would have arrived already.
can’t - indicates lack of skill to do something or impossibility of something happening. For example: She can't have taken the bus. She had no money with her.
might\may - indicate some degree of probability and possibility, but not a high one. For instance: I might call you tomorrow, but I'm not sure. / He may have forgotten about the meeting. Let's give him a call.
Having the explanation above in mind, we can answer:
a) He can't be from Cyprus.
b) He might have been reading.
c) Devkota may have written that poem.
d) She must have passed the exam.
