PrepTest 101

Incorrect. This answer raises the opposite relationship of what the argument relies on. The argument depends on TV influencing people's diets, not people's diets influencing what people on TV eat/drink.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
Food/drinks on TV are bad for you
Therefore - TV is bad for your diet

Answer Anticipation:
The question asks us to find a "presupposition" on which the health officials' argument depends. While "presupposition" may be a bit fancier than we're used to seeing, the "depends" lets us know that we're dealing with a Strengthen with Necessary Premise question.

Looking at the health officials' argument, we can see that they conclude watching TV is bad for your diet. Why? Because the foods/drinks that show up on TV tend to be bad for you.

That's a pretty big jump! Just because you see food or drink on TV doesn't mean that you're going to start eating/drinking only those things low in nutritional value. It's possible you can see an ad for a Big Mac and then go eat a salad with light dressing. The argument relies on TV influencing people's diets, so let's find an answer making that connection.

Answer Explanation:
This answer, on the other hand, makes that connection. The health officials assume that TV can influence people's diets. If we negate this answer—seeing food/drinks on TV doesn't increase the likelihood that viewers will consume it—then the answer falls apart. This answer is thus correct.

Key Takeaway:
Look out for directional words on the LSAT. Here, "influence" is directional—it establishes what's the cause, and what's the effect. A couple answers reversed that relationship and thus could be ruled out quickly.

Incorrect. This answer suggests that the food/drink industry believes they can influence people's diets by putting their food on TV, but that's not required for it to actually influence people's diets.

Incorrect. This answer is similar to (A) in that it reverses the relationship assumed by the stimulus a bit. Here, people start with diet preferences, and then they watch TV/enjoy characters that match the habits they already have.

Incorrect. While the health officials do draw a connection between TV and people's diets, the argument doesn't require them to be able to predict the foods/drinks that will become popular, just for a connection to exist.