Find the Confidence Interval

Find the confidence interval.
-Insurance companies track life expectancy information to assist in determining the cost
Of life insurance policies. ABI Insurance randomly sampled 100 recently paid policies
And determined the average age of clients in this sample to be 77.7 years with a standard
Deviation of 3.6. The 90% confidence interval for the true mean age of its life insurance
Policy holders is

A) 77.1 to 78.3 years
B) 76.87 to 80.33 years
C) 75.4 to 80 years
D) 74.1 to 81.3 years
E) 72.5 to 82.9 years