Explain the difference between using ‘must have’ and ‘might have’ for past deductions.

A. The use of ‘must have’ suggests a higher level of certainty or confidence in the deduction, while ‘might have’ suggests a lower level of certainty or confidence.

B. The use of ‘must have’ and ‘might have’ is interchangeable in past deductions.

C. There is no difference between using ‘must have’ and ‘might have’ for past deductions.

D. Using ‘must have’ and ‘might have’ in past deductions depends on the speaker’s mood.