In a Manufacturing Process a Machine Produces Bolts

Multiple Choice

In a manufacturing process a machine produces bolts. The lengths of the bolts follow a normal distribution with an average of 3 cm and a variance of 0.03 cm2. If we randomly select three bolts from this process:
-What is the probability the mean length of the bolt is at least 3.16 cm?

A) 0.9772
B) 0.0548
C) 0.9452
D) 0.4452
E) 0.0228