According to the local real estate board, the average number of days that homes stay on the market before selling is 78.4 with a standard deviation equal to 11 days. a prospective seller selected a random sample of 36 homes from the multiple listing service. above what value for the sample mean should 95 percent of all possible sample means fall?

(a) about 64 days
(b) about 79.3 days
(c) cannot be determined without knowing whether the population is normally distributed.
(d) approximately 75.4 days
(e) 93.2 days