Fossil-fuel producers say that it would be prohibitively expensive to

EXPLANATION FROM Fox LSAT

The conclusion here is, “This claim is probably false,” because it’s a prediction and the remainder of the argument sets out to prove this prediction. The evidence is this: “several years ago, they couldn’t solve the CFC problem either, but they were forced to, and they did it.” Therefore, the logic goes, their current claim that they can’t solve the CO2 problem is probably false.

Ideally, this argument will make you mad. Here’s my objection: Can’t they have been wrong last time, and still be right this time? What the eff does the CFC issue have to do with the CO2 issue anyway? Maybe the two are similar, but couldn’t they be completely different, according to the limited information we were given? We don’t have any idea, because the argument neglects to tell us. This is a huge weakness in the argument… this is where King Hippo’s pants fall down.(See www.youtube.com/watch?v=dFIbzmYTIGc for a short video of Little Mac defeating King Hippo on the original Nintendo Entertainment System.)

To strengthen the argument, I would ideally like to plug this gap. So something like, “Anything that is true of the CFC issue is also true of the CO2 issue,” would fit in nicely. The correct answer might not be exactly that, but I’m predicting that it will be that, or something similar to that.

A) This isn’t what we’re looking for. Let’s not bother with it until we go through all five answer choices.

B) Same explanation as A.

C) Same explanation as A & B.

D) This isn’t perfect, but it’s the closest so far because it suggests that CO2 could be phased out without more pain than phasing out CFCs entailed.

E) “Substitutes for fossil fuels” isn’t the issue, and it’s mentioned nowhere in the argument. The issue is simply, “Can the producers reduce CO2 emissions?” regardless of what mechanism the producers use. You can’t pick E without bringing in your own outside knowledge, which you’re not allowed to do.

So the best answer is D. This question is a great example of knowing how to strengthen an argument by first weakening the argument. You need to be on the attack. The correct answer is almost always related to some shortcoming that can be identified before looking at the answer choices.