So, validity is a machine where 1 + 1 = 2, and truth is interrogating 1, 1, and 2 to see if they're actually 1, 1, and 2? Does that metaphor work for these purposes?

Like, validity is quantitative and truth is qualitative?

I chose (A) as my first answer, and then overthought it on blind review and changed to (B). I made the assumption that a nomadic people left the area closest to North America, but the answer choice says nothing to that effect. It's entirely possible that they were nomadic and still stayed within that area. Choice (B) doesn't meaningfully weaken the author's assumption that the settlers had to come from Eurasia because they crossed the area closest to North America to get to North America. My original logic for choosing (A) was the logic LukeWilson identified in the analysis: if the projectile doesn't resemble any from Eurasia, then there's no reason for the author to assume it came from farther in Eurasia.

Sucks to get it wrong in blind review, but it's a nice reminder to be vigilant about whether I'm overthinking a question.

I was just about to select (B) and get the question wrong until I re-read all of the answer choices and realized my mistake. I read the passage, understood that "no headache pill stops pain more quickly" is a negative comparative, but I still nearly got it wrong. It wasn't until I re-read all of the answers that I realized that while you could conclude (B) (with weak support), (C) was the more accurate and precise conclusion for the passage.

This question is hard because the answer choices use precise language and the trap answer is very attractive, not because the logic is inherently complicated. In fact, I'd imagine a lot of people perfectly understood what the passage was saying and still got it incorrect because (B) is both an early answer choice and reasonably possible answer. They just completely skipped over (C).

What I took away from this experience is to always, always read every single answer choice and to double check that I understand exactly what each answer choice is saying. I should never stop reading just because I think I know the answer.

Long post, sorry, but I'm long winded:

Disney's argument is strongest because of the clear necessary-sufficient relationship in the argument. Walt having a Genie+ pass is sufficient for us to know that he must have completed one or both of the necessary conditions. Since we know that Walt has a Genie+ pass, then it must be true that he completed one (or both) of prostrating himself or sacc'ing the goats. Walt didn't prostrate himself before Goofy's alter, so he had to have done evil, evil things to ten goats. (I'm gonna be real I don't think I got the necessary-sufficient thing right because I never really felt like I got the explanation when it was given in high school, but the statement that follows remains true.)

Tigers is the middle strength argument because it presents evidence that can be entertained as a plausible explanation for why some mammals are not good pets. A pet that is prone to attacking me and can cause me very serious injury can be said to make for a poor domestic pet. Thus, not all mammals are suitable to keep as a pet. However, pets can be kept for a variety of reasons that have nothing to do with behavior or the danger to the owner. Maybe I like the danger and challenge presented by keeping a tiger as a pet? In that case, neither the aggression nor the danger are barriers to owning a tiger as a pet. Therefore, the premise can still be true, but doesn't strongly support the conclusion that not every mammal is suitable to keep as a pet. The danger and risk of injury actually increases the tiger's suitability as a pet.

Trash bin is the weakest because the evidence presented only suggests guilt, but doesn't directly validate it. For the claim made by the investigator to be true they have to show intent, action in reality, and possession. In other words, they need to prove that Mr. Fat Cat: (1) knocked over the bin; (2) did so with the intention of eating the salmon, and; (3) actually consumed (or took possession of) the salmon. To weaken the argument you can attack any of the three elements of the "crime" in question (in a variety of ways). The passage only presents circumstantial evidence of Mr. Fat Cat's guilt.