This is a Fill In The Blank question, which you can determine by noticing the big old blank space at the end of the stimulus. Fill In The Blank questions present a partial argument in the stimulus, then ask us to round the argument out by adding in the missing piece.

But from the question stem alone, we can’t tell whether the missing piece is a conclusion or a premise. Our first step, then, is to look for indicator words preceding the blank. If we find a therefore, for example, we’re in a Main Conclusion / Most Strongly Supported question; if we find a word like since, we’re in a Strengthen question.

Here, the phrase “It is clear then” tells us we need to provide the argument’s conclusion. To put it more precisely, we’re given a very specific (and quite grammatically complex) subject – desires that people believe products will satisfy – and tasked with supplying a predicate that is supported by the other claims in the stimulus.

This stimulus is very difficult to parse. Rather than walking you through the realistic process of arriving at the correct mental model, which likely involves a fair bit of backtracking and maybe even some notetaking, we’ll just present the structure as clearly as possible right off the bat.

According to our author, there is a wrong way and a right way to think about what ad agencies do:

WRONG
Ad Agency: Psst you should start desiring a sports car.
Person: Hey I think I desire a sports car!
– Person buys a sports car –

RIGHT
Person: I desire to feel cool.
Ad Agency: Psst a sports car would make you feel cool.
Person: Hey I think a sports car would make me feel cool!
– Person buys a sports car –

In the wrong account, ad agencies cause people to desire products. In the right account, ad agencies cause people to match products up with their pre-existing desires.

As mentioned above, our fill-in-the-blank challenge is to provide a predicate that applies to the subject the desires that people believe products will satisfy. Which like... what?

Well, in the “right” account, the Person has a desire to feel cool, and believes a sports car will satisfy that desire. So the desire to feel cool is the one we’re talking about. You know, the (spoiler alert) pre-existing desire the Ad Agency preys upon to sell sports cars.

Navigating all that logic up front and arriving at such a specific anticipation is theoretically possible but not very realistic. On test day it’s certainly worth backtracking and rereading until you have your head wrapped around the argument’s broad structure, but practically speaking the process of finding the correct answer is aided significantly by the answer choices themselves, many of which just say clearly unsupported stuff. So let's proceed with process of elimination.