A Dependent T-Test Is Used to Identify If Any

A dependent t-test is used to identify if any?

A) Difference in means between groups containing different people when the data are normally distributed, have equal variances and data are at least interval.
B) Difference in means between groups containing different people when the data are not normally distributed or have unequal variances.
C) Difference in means between groups containing the same people when the data are normally distributed, have equal variances and data are at least interval.