How will the right answer fit in terms of support and conclusion?

Only the right answer will be a conclusion supported by the passage. You wouldn’t know that just from the prompt, since support could complete the passage on a different question. But since the blank follows “Therefore,” it’s clear the right answer will be the main conclusion.

Highlight the main conclusion in the passage, if there is one:

There’s an intermediate conclusion in this passage. That’s support for the main conclusion that also gets supported by another statement in the passage. But nothing to highlight, since the right answer will fill in the main conclusion.

Cerrato: [BACKGROUND]. But because [SUPPORT], [INTERMEDIATE CONCLUSION]. Therefore, ______.

Map the wording of the answers to the wording of the passage:

(A) full-time workers are likely to lose jobs…

Nope, that’s the opposite of what the passage says. Right before “Therefore” the author said “companies are unlikely to replace” the satisfied, full-time workers.

(B) the companies earning the greatest profits…

…are never mentioned in the passage. No valid conclusion can bring in stuff the rest of the argument never mentions or references.

(C) dissatisfied part-time workers are unlikely to threaten the jobs…

This maps perfectly. The support says “companies are unlikely to replace” one group with the other, so it’s reasonable to conclude those people’s jobs are “unlikely” to be threatened.

(D) …is only partly caused by their greater job dissatisfaction

We always recognize when an argument uses cause-and-effect. This one didn’t, so a conclusion about cause-and-effect doesn’t make any sense. There would have to be some other cause mentioned in there to reach a conclusion that dissatisfaction is “only partly” the cause.

(E) …only when they are unable to hire full-time workers

There’s nothing in the passage about who’s able or “unable” to hire full-timers. If you liked this one, you’re adding in a step or two of your own reasoning. Right answers never make you do that.

(C) is the correct answer.