When sampling from a non normal distribution with a known variance, which statistics should be used if the sample size is small and if sample size is large?

a. Large Sample = z-Statistic | small Sample = not available
b. Large sample = z-Statistic | Small Sample = Z-statistics
c. Large sample = t-Statistic | small sample = not available
d. Large sample = z-Statistic | small sample = t-Statistic