Sampling Distribution of the Sample mean

Let X be the number of hours a legal professional spends attending meetings during a typical work day. Assume that X is normally distributed with a known standard deviation of 3.6.

A sample of 250 legal professionals are surveyed, and the sample's mean response was 2 hours. The sampling distribution of the sample mean is

a.exactly a normal distribution

b.approximately a normaldistribution

c.a t-distribution.

d.unknown