Underline the correct answer

A: Good morning, madam. May/must
I help you?

B: You might/mustn’t be able
to. I need a ball of wool that is the same color as my jumper.

A: Just a moment, please. I must/mustn’t
look in the stock room. We might/might
not have some left. I’m not sure.

B: The wool must/mustn’t be
exactly the same color, it must/mustn’t be
different.

A: Could/Mustn’t I ask you a
question, madam?

B: Yes.

A: What do you want the wool for?

B: I could/must finish
knitting this jumper. It only has one sleeve at the moment!