I also chose E and don't know if my reasoning makes complete sense but I decided to comment for my own benefit in trying to understand why E is wrong and C is right. Hopefully it helps though!
AC E is wrong because a sample group of (let's say) 18-25 year old psych students is not representative of ALL people. It neglects to include everyone under or over that age group or people who are not in psych course. Therefore, this group does not make for a "good" study or sample group to be able to say that MOST people would like to be informed that they have a serious medical condition.
AC C is not biased because the researchers don't necessarily need to have a background in medicine or even analytics as you said. I'm sure it would strengthen the argument if they did have experience with conducting research but it doesn't wreck the argument (imo). It basically does nothing but as he's said before; the right answer could do absolutely nothing for the argument.
I also chose E and don't know if my reasoning makes complete sense but I decided to comment for my own benefit in trying to understand why E is wrong and C is right. Hopefully it helps though!
AC E is wrong because a sample group of (let's say) 18-25 year old psych students is not representative of ALL people. It neglects to include everyone under or over that age group or people who are not in psych course. Therefore, this group does not make for a "good" study or sample group to be able to say that MOST people would like to be informed that they have a serious medical condition.
AC C is not biased because the researchers don't necessarily need to have a background in medicine or even analytics as you said. I'm sure it would strengthen the argument if they did have experience with conducting research but it doesn't wreck the argument (imo). It basically does nothing but as he's said before; the right answer could do absolutely nothing for the argument.