What is the probability that a month picked at random will have 31 days?

A. 5 over 12
B. 4 over 12
C. 7 over 12
D. 8 over 12

There are 12 months in a year, and 7 of them have 31 days. So the probability of picking a month with 31 days is:

7/12

Therefore, the correct answer is C.