Why is A the right answer?

Let's take a look at (A). (A) says, "There is no evidence that there are wavelengths of sunlight that lead to both sunburn and melanoma." We're looking to weaken the argument in the stimulus. (A) tells us that there isn't a reason to think that the sunburn and melanoma are from the same waves. From this, we have reason to think that if someone has a sunblock that is blocking the sunburn rays, it still might not be blocking the cancer rays. Thus, (A) weakens the argument and is the correct answer choice. Does this make sense? Let us know if you have any other questions!

i think (E) is better in that it suggests that the chemicals in sunblock could cause melanoma.