The manufacturer of a certain energy bar advertises that their energy bar contains 14 g of protein. You work for a nutritional health agency and are asked to test this claim because many consumers believe that the protein level is lower. You find that a random sample of 20 energy bars have mean protein level of 13.1 g and a sample standard deviation 1.5 g. Do you have enough evidence to reject the manufacturer's claim?What assumption is necessary for this test to be valid?

A: None. The Central Limit Theorem makes any assumptions unnecessary.

B: Thepopulation ofprotein levelof all energy barsis normally distributed because of the small sample size.

C: The population variance must equal the population mean.