This is a pretty unsatisfying explanation of what is ultimately a flawed question. The first issue is that the local CDC makes no claim about rabid raccoons. It makes a claim about the severity of the rabies outbreak, using raccoons as an example (it is reasonable, I think, for us to bring the knowledge that other animals can catch rabies). The second issue, closely related to the first, is in the grammar and wording of the first sentence of the stimulus in which it is implied that the conclusion of the city's report is that the epidemic is more serious. This leads to ambiguity about the nature of the discrepancy we're trying to resolve: is it the discrepancy between the raccoon infection numbers? Or, is it the discrepancy between the claim in the first report (that the epidemic is worse now) and the lower number of infected raccoons in the second.

B explains why the number of confirmed-rabid raccoons decreased over the last two years, whereas A explains why the outbreak is worse now, despite there being fewer confirmed-rabid raccoons. Naturally, if a large proportion of raccoons succumbed to rabies in the last year the outbreak should actually have gotten better--unless the rate of rabies in other animals has increased.

#feedback

We're not really assuming that. We're just assuming that more of it arrives after 3 days because most mail still takes 3+ days to delivery. That weighting of the average delivery time to 3+ days isn't coming from correctly addressed mail, and it isn't coming from correctly addressed mail that's been damaged (because we know that that's rare), so it must be coming from incorrectly addressed mail--both damaged and not.

I agree with you. There is also no reason given in the stimulus for why an art dealer's attribution should be, or could be classified as a "traditional attribution", which would seem to make AC A irrelevant.

I think it's a square-rectangle situation. Cost is an impact, but not all impacts are costs (some may be changes to the character of science).

My performance on SA and PSA improved dramatically after going through the NA and MoR sections and studying those for a while.

Heya lol; I definitely see your point, but I think your example is running up against the limits of the English language. In your original example, even if you shift the emphasis from the conclusion to the whole argument, the inclusion of "if" grammatically removes necessity. Because the issue is not "if" the argument assumes something–the argument doesn't really have a "choice" but to assume the necessary assumptions.

Your example of a potential SA question struggles the same way. The conclusion of an argument almost never "requires" a sufficient assumption, because it is just one of a potentially infinite number of sufficient assumptions, depending on the stimulus.

Potentially your NA example could be turned back into a NA question stem if instead of "if" you substituted "only if"? I can't immediately think of a way to alter the example SA stem though. "Could require" would be an extremely clumsy/contradictory way to do it I guess.

Your example question is still asking for a sufficient assumption.