A and B

@hanna The flaw in the argument is mistaken negation, which we also see in B: Only Xs do Y. Thus, Z must not be X, since they don't Y. (Missing that just because only Xs do Y doesn't mean all Xs do Y.) A is flawed for sure, but it goes in a different direction. It tells us that only on Fridays can employees dress casually. Hector isn't, so he isn't an employee. The argument would be similar in pattern if it were: Only ABC Corp's employees can dress casually on Fridays. Hector is dressed formally on Friday, so he must not be an ABC employee. Does that help?

Can you please diagram answer choice C for me? It seems so similar with answer B that if it had come first, I would have chosen it. Thanks

@Philidjel, Answer choice (C) is completely different from answer (B) Answer choice (B) correctly mirrors the flaw of the stimulus. The stimulus maps to quota - ->experienced salesperson and the conclusion the writer makes is /quota - ->/experienced salesperson @Anita describes this flaw in greater detail above. Moving on to (C), it states, "only oceanographers enjoy the Atlantic in midwinter. Thus, we may expect that Gerald does not enjoy the Atlantic in midwinter, since he is not an oceanographer" This translates to Premise: Enjoy Atlantic midwinter - ->oceanographer Conclusion /oceanographer - >/Enjoy Atlantic midwinter The conclusion of (C) is a valid contrapositive of the premise. This is sound reasoning, and this does not parallel the flawed reasoning in either the stimulus or in (B). Hope this helps. Let us know if you have any other questions!

@Philidjel can you please explain to me what words should have triggered me to diagram: not Oceanographer -> not enjoy the Atlantic in midwinter? ... for C? I diagrammed this the other way around. ...I'd like to know how I can avoid interpreting the conclusion of C incorrectly again. Thanks.

@mprezzy I spent 9 minutes on this one! After reading on the thread a bit, it seems like the final premise that leads to the conclusion acts a bit like the sufficient while the conclusion acts a bit like the necessary condition. That may be incorrect, but it seems to lead to the correct answer most (if not all) of the time. So, for this one, C should be something like: Only oceanographers enjoy the Atlantic in midwinter. Thus, we may expect that Gerald does not enjoy the Atlantic in midwinter, since he is not an oceanographer. EAM --> O Thus (conclusion/necessary), since (premise/sufficient). Pr: not O C: not EAM Or, you might be able to think of it in a S/N format: not O --> not EAM I could be using terrible logic with this, but thinking about it in this way is helping me figure out what the sufficient and necessary conditions are.