Top Law Schools

Each of the following weakens the argument except--

TCR to this question is C: some of the researchers conducting the studies had no background in medicine. I chose E: The people surveyed were all young students in intro psychology courses.

I don't see how C is the correct answer. I would imagine that the researchers not having a medical background might affect the results since the question in the survey is about a medical issue. I chose E because it seems completely irrelevant to the premise, and therefore wouldn't weaken the argument. Can someone explain why C is the correct answer? I just don't see how respondents being psychology students would weaken the argument.

Well, I guess because E states they were *all* psychology students, it would weaken the argument since it limits the survey to a very specific group of people, whereas the background of the researchers wouldn't be relevant.