What is the difference between ‘may’ and ‘might’ in terms of expressing possibility?

A. May and might are only used in formal writing and not in spoken language.

B. May is used to express a higher possibility, while might is used to express a lower possibility.

C. May and might are interchangeable and can be used to express any level of possibility.

D. May is used to express a lower possibility, while might is used to express a higher possibility.