Question 15. answer C needs to be worded more carefully in my opinion

"Incorrect. While these two publications are the top sellers, that doesn't mean most people who purchase something at these stores buy one of the two. The top sellers could be purchased by only a small minority of students while still beating out the other publications by a wide margin." So it says in answer c most people who purchase PUBLICATIONS. It speaks nothing to purchasing other things from the store. The explanation of the answer being incorrect is drawing a comparison saying that just because most people by these publications does not mean that it is the thing bought most in the store. The problem with this is the answer itself says publications specifically. The only way I can understand that answer c is incorrect is if you are making the claim that best-selling is not the same as most-selling which by definition of the word best does not make sense. Is there some detail that I missed here? Unless best selling is not synonymous with most selling? How does this make sense?