Answer:
b. paired samples using the t-distribution.
Step-by-step explanation:
In statistics and research methods, the paired sample t-test or distribution is described as a technique that consists of two different "competing hypotheses" including the alternative hypothesis and the null hypothesis.
The given test doesn't assume that the given variance of the given population is the same or equal. It is being used when an experimenter is interested in testing the difference between two different variables possessing the same subject yet these variables are being separated or divided by time.
As per the question, the given statement represents the test statistics as paired samples using the t-distribution.