Please explain

Why is E incorrect?

@Cynthia-Lee and @Shyi-Zhang, Happy to help! In the stimulus, we're told that over the last 25 years, sunscreen use has risen, but skin cancer rates have also gone up. From this, the argument concludes that sunscreen likely doesn't reduce skin cancer risk. In examining this argument, it seems decent upon first glance. If sunscreen use has risen over the last 25 years, then if it helped prevent or reduce skin cancer risk, we'd think that we would have seen a decrease in skin cancer rates over the same time (but the opposite has happened). The question is asking us to pick an answer that would weaken the argument. In other words, we're looking for an answer choice that suggests that sunscreen does help to reduce skin cancer rates. What if there were an alternative cause of the rising skin rates, or what if sunscreen use were concentrated in certain regions where skin cancer was actually going down (but overall, skin cancer nationwide or globally was still going up)? (E) says, "Those who use sunscreens most regularly are people who believe themselves to be most susceptible to skin cancer." (E) is basically saying that the people who use sunscreen are the ones who think they have a higher skin cancer risk. The problem with (E) is just because these people think they are most susceptible to skin cancer doesn't necessarily mean that they are. Additionally, even if we assume that they're correct in that they're more likely to develop skin cancer since they're using sunscreen most regularly we would suspect that if the sunscreen actually worked, we would be seeing their rates go down. Remember, we're trying to weaken the argument, and (E) isn't providing us with anything to help us accomplish our goal of weakening. We can get rid of this answer choice. (B) says, "Skin cancer generally develops among the very old as a result of sunburns experienced when very young." (B) provides us with information that would help to seriously weaken the argument because if people develop skin cancer when they're really old, then it's reasonable that the increase in sunscreen use over the last 25 years wasn't over enough time to meaningfully affect skin cancer rates among the elderly, where skin cancer often shows up. It's possible that these people already had their bad exposure to the sun before the last 25 years. It's even possible that they started using sunscreen a lot over the last 25 years but had already had too much sun exposure and set themselves up for skin cancer later on. This answer choice suggests that it's still possible that sunscreen use could be effective in reducing skin cancer risk, so this helps to weaken the argument. (B) is the correct answer. Does this make sense? Let us know if you have any more questions!