One summer, floods covered low-lying garlic fields situated in a region with a large mosquito population. Since mosquitoes lay their eggs in standing water, flooded fields would normally attract mosquitoes, yet no mosquitoes were found in the fields. Diallyl sulfide, a major component of garlic, is known to repel several species of insects, including mosquitoes, so it is likely that diallyl sulfide from the garlic repelled the mosquitoes. Which of the following, if true, most strengthens the argument?

Explanation: The argument concludes that **diallyl sulfide** (from garlic) repelled the mosquitoes. We need a premise that supports this chemical as the primary cause by eliminating other possible causes for the absence of mosquitoes. If **many insect species NOT repelled by diallyl sulfide were found** in the flooded fields, it suggests that conditions other than diallyl sulfide (like a generally low regional mosquito population (Option B), extreme weather, or water quality) were NOT repelling insects universally. This strengthens the conclusion that the specific repellent, diallyl sulfide, was the reason the mosquitoes (who are susceptible to it) were absent.