Answer:
A and D
Explanation:
Matched pairs t test is used for paired data. Data sets are "paired" when the two sets have the same number of data points and each data point in a set is related to only one data point in the other set.
A good example is before/after data. Each set has the same number of data points, and each data point in the after set is related to one in the before set.
B is not an option because, although the samples are the same size, there is not a paired relationship between the sets.
C is not an option because the samples are not the same size.