Given a text T, and several options, according to the question posed in the text T to choose the most appropriate option from the options as the answer, please directly output the most appropriate option, do not need to output the explanation.

To test a null hypothesis that the mean of a normalized population is no larger than a particular value, which of the following tests is most appropriate if the sample size is small and population variance is unknown?
Option A:A z-test
Option B:A t-test
Option C:A non-parametric test

Answer: B