jessamylockard,
Thanks for the question! This is a weaken question, meaning that the correct answer will serve to weaken the conclusion. So what is the conclusion? The author states the premises and then closes by saying the conclusion "
Thus, for most people the generally more expensive long-term training is unwarranted." In other words, the author is concluding that there usually isn't a reason for people to get long-term treatment for anxiety. We should be able to have a really strong prephrase here: if the conclusion is that long-term treatment is usually unwarranted, we should expect the correct answer choice to provide us with a reason or explanation that suggests that long-term treatment
is warranted/useful/desirable. With that idea in our heads, let's move to the answer choices.
Answer choice (A) reads: "
A decrease in symptoms of anxiety often occurs even with no treatment or intervention by a mental health professional." If this were true, it suggests that perhaps no treatment is warranted or necessary - but that doesn't weaken our conclusion that long-term treatment is ineffective (if anything, it strengthens it, as long-term treatment is still a form of treatment). Therefore, it is not our credited answer. Be really careful - it sounds like your psychology background may have tripped you up a bit here
Remember that the LSAT does not require any prior, specialized knowledge of us - so even if we know a statement like answer choice (A) to be true, that is irrelevant - all that matters is if, if it were true, it would weaken the conclusion. It does not, and so it is incorrect.
Answer choice (B) reads: "
Short-term relaxation training conducted by a more experienced practitioner can be more expensive than long-term training conducted by a less experienced practitioner." This answer choice suggests that in some cases, short-term relaxation training may be more expensive than long-term training, but does not get to the core issue of training effectiveness. Because this answer choice doesn't suggest that long-term training could be effective, it is not the credited answer choice.
Answer choice (C) reads: "
Recipients of long-term training are much less likely than recipients of short-term training to have recurrences of problematic levels of anxiety." Here we go: this is a clear reason that long-term training might be preferable to short-term training (it leads to fewer reoccurrences of anxiety). Because this answer choice directly provides us with a reason that long-term treatment might be warranted, it attacks and weakens the conclusion, and is our credited answer.
Hope that helps!
Alex