Going with A. 62% of the people who returned the questionnaires were in favor of the change, but how many people actually returned it? If 90% of the people returned the questionnaire, then 62% of 90% is 55.8%, so more than half of their readers are in favor of the change.

Think more about "A"

The only potential pitfall in A is that the company may not have sent the questionnaire to everyone who reads the magazine, in which case that 90% figure would be meaningless (because it could be 90% of, say, the 10% of the readership who actually got the survey). But if that's the case, then the next best answer (C) suffers from a smiliar problem - "The percentage of surveyed readers who liked the change" is NOT the same as "the percentage who returned the questionnaire". C is trying to get you to equate the 62% who liked the change to percentage among total readership who would like it and conclude, "Okay, so 62% of everyone who would read the magazine would like the change." But you can't make that claim, because it's actually stating that the percent of ALL people who were surveyed who like the change. We don't know how many actually liked it, just how many OF THE ONES WHO RETURNED IT do.

That's kind of confusing, so here's an example. Say 100 people were surveyed. Some of them returned the surveys, and some of them didn't. Of the ones who did return it, 62% liked the change. C says that the percentage of the entire 100 people who liked the change would be reflective of how many people in general would like it. But we don't know that percentage. Say that all 100 people returned the survey. Then 62 of the people surveyed liked the change, meaning that 62% of all people would like the change. But what if only 50 people returned the survey, and the other 50 all disliked the change? Then 62% of that 50 is 31 people - which is only 31% of the entire sample, meaning that only 31% of the entire population would like the change.

The only other possibility would be E, but unless I'm misreading it, E is saying that the people who like the old format (and thus would answer with a negative survey) were underrepresented, so the 62% figure in favor of changing would need to be adjusted way down.

IMO C