Passage Summary: A study found that workers in sulfur factories are much worse at identifying smells than people in other jobs, leading researchers to conclude that sulfur fumes permanently ruin your sense of smell.

Conclusion: Long-term exposure to sulfur fumes causes lasting damage to a person's ability to smell.

Reasoning: A study showed that factory workers exposed to sulfur fumes were significantly less successful at identifying various scents than a control group of workers from other industries.

Analysis: This argument relies on a study to establish a causal link, but it leaves several doors open for attack. We could weaken it by suggesting the two groups weren't comparable to begin with, or by showing that the 'damage' wasn't actually permanent. Since this is a 'Weaken Except' question, your task is to identify the one answer choice that does NOT undermine the conclusion. Four choices will likely provide alternative causes for the poor performance or challenge the study's methodology, while the correct answer will be irrelevant or perhaps even slightly supportive.