Passage Summary: A sociologist argues that big pay gaps aren't the problem people think they are. Instead of causing trouble, these gaps help companies stay flexible. The real cause of social tension is when wages don't move at all.

Conclusion: The idea that significant pay gaps between the highest and lowest earners will necessarily lead to social unrest is incorrect.

Reasoning: Large wage differences allow businesses to adjust their hiring practices more easily, and social friction is actually caused by stagnant or slowly changing wages rather than the size of the gap itself.

Analysis: The sociologist attempts to dismiss a causal link between wage gaps and social friction by proposing an alternative cause: wage stagnation. To make this argument hold water, the author must assume that a high wage differential does not itself lead to the very stagnation that causes friction. We should look for an answer choice that ensures these two factors—high differentials and wage movement—are compatible or that the differential doesn't trigger the friction through some other hidden mechanism. It's a classic 'A doesn't cause B, C causes B' argument structure.