What type of procedure should we use, t or z?

A factory that produces milk randomly tests the fat content of batches of milk that is supposed to be 2% milk fat. To test the jugs they take a random sample of 5 jugs per batch. The company knows the milk fat in the population varies on average 0.1%. Their sample yields a sample mean of 2.02%.

A) One sample z test for a mean
B) One sample t test for a mean
C) A matched pairs t test for the mean difference