CFA1 level 1 统计题

CFA1 level 1 统计题
Which of the following statements about hypothesisatistic testing involving a z-statistic is least accurate?
A.the p-value is the smallest significance level at which the null hypothesis can be rejected.
B.A z-test is theoretically acceptable in place of a t-test for tests concerning a mean when sample size is small.
C.If the confidence level is set at 95%,the chance of rejceting the null hypothesis when in fact it is true is 5%.
请给原因.答案的原因有点牵强吧.希望有人解释地更好点