Identify the Question Stem: The words most useful in evaluating indicate that this is an Evaluate the Argument problem.
Deconstruct the Argument: There was an economic downturn and a lot of companies laid people off. Economists made a prediction: People who weren't laid off would reduce their non-essential spending because they would be worried about the economy in general. But, because there hasn't been an increase in money saved in savings accounts, the author concludes that the economists were wrong.
Pause and State the Goal: The answer choices are in the form of questions. You're looking for a question that could help you to strengthen or weaken the conclusion, depending on the answer to that question. In other words, the right question will help you to evaluate whether the author's claim is more likely to be valid or whether the economists' prediction might have been valid after all.
Work from Wrong to Right:
(A) Knowing that, for example, the manufacturing industry or the health-care industry was most impacted doesn't help to evaluate whether the author's claim is correct or whether the economists actually were right in their prediction.
(B) The laid-off workers are likely not going to be able to increase their savings while looking for a job, of course, but without knowing the proportion of laid-off workers to employed workers and their corresponding average savings, it cannot be determined whether the laid-off workers' loss in savings is offsetting employed workers' additional savings.
(C) CORRECT. If the cost of necessities has increased by 100%, then maybe people have reduced their non-essential spending—but then they had to spend that money on essentials, rather than save it. In other words, the economists might have been right and the author might be wrong—this weakens the author's claim. If, on the other hand, the cost of necessities has stayed exactly the same or even decreased, then the author's claim is more likely to be valid; in other words, this choice would strengthen the author's claim. Since the answer to this question could either strengthen or weaken the argument, it's the best question to ask in order to evaluate that argument.
(D) If 90% of laid-off workers have savings accounts, or if 10% of laid-off workers have savings accounts, how is the argument impacted? It isn't, because the argument is about the fact that there hasn't been an uptick in savings for all people, including those who weren't laid off.
(E) It might be useful to know whether the average salary has changed since the layoffs. But knowing what the average salary is now without knowing what it used to be doesn't provide any useful information to speculate as to whether people are likely to have changed their spending or saving habits.
The correct answer is (C).
