PROBLEM 5. It's known that the amounts of time required for room-service delivery at a certain Marriott Hotel are Normally distributed with the average delivery time of 20 minutes. Answer the following questions.

**Question** If a random sample of 12 deliveries was selected instead, and the standard deviation of these delivery times was found to be 7.87 minutes, find the probability that their average delivery time is less than 25 minutes.

a) 0.9861

b) 0.0250

c) 0.9750

d) None of the above