Which of the Following Is Not an Assumption of the T-Test

Multiple Choice

Which of the following is not an assumption of the t-test?

A) The data should be ordinal or nominal.
B) The population distribution of scores should be symmetrical.
C) The population mean ( $\mu$ ) is known,but the population standard deviation ( $\sigma$ ) is not known.
D) The sample size is typically less than 30.