A random sample of size 15 is taken from a normally distributed population with a sample mean of 75 and a sample variance of 25.

A random sample of size 15 is taken from a normally distributed population with a sample mean of 75 and a sample variance of 25. The upper limit of a 95% confidence interval for the population mean is equal to: 

A) 77.530 

B) 72.231 

C) 74.727 

D) 79.273