Happy to help, bac435! Answer A, "the way in which sulfates in the earth’s atmosphere produce an effect on temperatures", is mentioned in the passage at lines 26-30, where the passage states:
Sulfates from natural sources such as volcanoes as well as from human technological sources tend to counteract the heating effect of greenhouse gases by reflecting solar energy back into space.
This tells us the way that sulfates produce an effect on temperature - they reflect solar energy back into space, lowering temps ("counteract[ing] the heating effect").
None of the others are mentioned in the passage, and since the question asked which of the five answers was mentioned, the four that were not mentioned are crossed out as losers.
Did you have another contender under consideration, something that you believed was mentioned? If so, you would need to be able to identify the line numbers where you found it. That's the real test for the answers to a question like this - can you put your finger on it, literally? Not just something alluded to, or that we as the readers might assume, but actually mentioned explicitly in the text.
Adam M. Tyson
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