A Lawyer Researched the Average Number of Years Served by 45

Multiple Choice

A lawyer researched the average number of years served by 45 different judges on the Supreme Court. The average number of years served was 13.8 years with a standard deviation of 7.3 years. What is the
95% confidence interval for the average number of years served by all Supreme Court judges?

A) $11.7 < \mu < 15.9$
B) $11.8 < \mu < 15.8$
C) $12.9 < \mu < 16.9$
D) $12.5 < \mu < 17.3$