Answer:
The correct options are (c) and (d).
Explanation:
The assumptions made before using a t-distribution for a hypothesis test are:
A sample size of 5 a sample size of 50 sample will not be accurate for a t-test because on of the sample size is, 5.
This sample size is very small and when plotted will not follow a normal distribution.
The sets that differed in variance will not be accurate for a t-test because for using a t-test homogeneity of variances is assumed.
Thus, the correct options are (c) and (d).