The argument concludes that an obvious explanation for a certain phenomenon is not true (the cafeteria food didn’t make the campers sick), despite evidence to the contrary (they only ate cafeteria food). The stimulus also ignores an obvious explanation to a phenomenon, despite evidence to the contrary, so (A) matches.

Wrong flaw. (B) gives a phenomenon (the second prototype performing worse in bad weather), and then provides an explanation for this phenomenon. Although there is little evidence to support this explanation, there is also no obvious explanation that (B) overlooks. The stimulus, however, does ignore an obvious explanation, so (B) doesn’t match.

Wrong flaw. Even if each swimmer loses more than they win, for example, 60% of the time, someone will still win the meet. Because of this fact, (C) is a completely invalid argument. The stimulus, however, ignores an obvious explanation for no reason, so (C) doesn’t match.

Wrong flaw. (D) gives a phenomenon (Marjorie’s cavities being on the left side of her mouth), and then provides an explanation for this phenomenon. Although there is little evidence to support this explanation, there is also no obvious explanation that (D) overlooks. The stimulus, however, does ignore an obvious explanation, so (D) doesn’t match.

Wrong Flaw. (E) looks at a current trend (bigger tomato plants) and concludes that the same trend will be true for peas. This is flawed because it overlooks the many differences between tomatoes and peas. The stimulus, however, ignores an obvious explanation for no reason, so (E) doesn’t match.