May I use your calculator? – Of course, you ……… ; I don’t need it now.
a may b can’t c can d may not
The answer given is 'c'. I would like to know why 'a' isn't correct? I know that 'May' and 'Can' can be used to ask for permission. However, 'may' is more formal. Could it be because the subject 'you' makes 'may' not acceptable as it used only with 'I' or 'we' when used to ask for/give permission?
I've heard of the famous response, 'Yes, you can but you may not,' that demonstrates the difference between 'can' for ability and 'may' for permission. Yet, here 'may' is used with 'you'. So I got confused.
From an exercise on Longman NewHelloEgypt