I got this one wrong originally, but recognized my mistake in using the Negation Technique - instead of negating "Some" in answer D as "None"/"No", I negated it as "some are not," and I thought to myself, "Okay, this isn't necessary to the argument, as some films not being in their original (deteriorating) material does not preclude at least one, if not more, films from being in their original material, thus allowing them to not be preserved." BUT, upon reflection, I recognized my oopsie poopsie and thought I would remind folks (& mostly myself...) to remain in tip-top shape re: their negations if they choose to employ the Negation Technique to narrow down correct/incorrect answers, as the negation of "Some" is "None," and the negation of "All" is "Not all/Some are not". Happy assuming, everyone!

@DominicCruse Hey Dominic! I like to think of it this way - "in-," when attached to the front of a word, is essentially akin to the word "not" in terms of how it modifies that word. For example, if someone is "incapable" of making decisions, it means that they are "not capable" of making decisions - or, in other words, "incapable" is the logical opposite/negation of the word "capable". As such, "insincere" is analogous to "not sincere," AKA the logical negation of "sincere", for if someone is acting insincerely, it means that they are not acting in a sincere manner. Thus, "in-" can act as "not" for the purposes of negation in many instances, including the one posed within this question. Apologies if this confused anything further, but I hope this helps!

@DaisukeKaga I was thinking the same thing, especially because the question stem uses the language of "... if which one of the following is assumed?"

@Daisy228 I think those are definitely two valid inferences based on the premises provided, even if the larger chain ultimately concludes that Hermes likes to eat wasabi!

@cegattbs Hey friend, you're not missing anything - you're just learning, and that is all good!

To recall from earlier lessons, when it comes to conditional logic (or much of the argumentation featured within the LR section, for that matter), it is not about the substance of the arguments and the clauses they contain, but rather, it is about the form of the argument. In other words, there can be some divergence when it comes to the real world (i.e., what seems logical and intuitive IRL) and the "LSAT world" (i.e., arguments given to us on the LSAT, including conditionals, causal relationships, etc.). Our brains in the real world may intuitively tell us that, if we know how to cast a certain funky plant charm, we can likely do some beneficial things with that charm, including being able to mix plant material into garden soil. But, the question stated that, in order to mix plant material into garden soil, you MUST [necessary condition indicator!] know how to cast the Herbivicus Charm. In other words, mixing plant material into garden soil guarantees that you know how to cast the charm, but knowing how to cast the charm does NOT guarantee that you actually went ahead and mixed the plant material into garden soil (i.e., your magical self may have gotten distracted with the latest episode of the Real Housewives of Hogsmeade, or had a little doomscrolling episode... we've all been there), although knowing the spell is required in order to do so. If you were to believe that knowing how to cast the charm inevitably leads to the action of mixing the plant material into the garden soil, based on the rules/conditions laid out to us in the question, that would be confusing sufficiency for necessity.

Hopefully this helps, and once again, never feel as if you are missing anything when a) you already know so much, b) you will continue to learn and internalize previously unfamiliar concepts/ideas, and c) you will continue to make significant strides in your studies. We've got this!

@CharlesUgorji Well put, Charles! I agree with your explanation, and also noted down that I thought that "But this is not a sustainable, long term solution" was a sub-conclusion/major premise.