Focus on the conclusion "People who take Vitamin C supplements tend to be healthier than average" the rest is junk trying to give an example of why a particular study. D weakens the conclusion.
Can someone expand on why A is wrong. The way I read the question, Group 1 was paid $1 to come up with a story for the contest. Group 2 was paid nothing to come up with a story. Thus the cash prize is insignificant and maybe group 1 just produced a worse quality of story. This is exactly what A is ...
If this would've been a MSS, which I had thought by just reading "most strongly.." I would've gotten this question right with answer E! Pays to read the whole stem, ha!