Suppose that 100 former customers of an online retailer were asked in an email survey whether they preferred free 3-day shipping or whether they preferred overnight shipping for $4.99. 75% said that they preferred free 3-day shipping. 70% of the customers were male. 80% of the males preferred free 3-day shipping.

Suppose a randomly selected customer prefers overnight shipping. What is the probability the customer is a male?

A. 25

B. 31

C. 19

D. 56