During the summer months, the prices of nonsmoking rooms with a king-sized bed in hotels in a certain area are roughly Normally distributed with a mean of $131.80 and a standard deviation of $29.12. A travel agent randomly selects prices of nonsmoking rooms with a king-sized bed from 15 hotels in the area. What is the probability that their average cost will be more than $150?
a) 0.0077
b) 0.3678
c) 0.2660
d) 0.1125