dont understand

Hi! We are trying to strengthen the environmentalists’ proposal in this question, so let’s first figure out what their proposal is. The stimulus tells us that “environmentalists propose replacing gasoline with methanol”, so we see that they would prefer using methanol (produces formaldehyde) over gasoline (produces benzene). So if it is true that formaldehyde is a less potent carcinogen compared to benzene, that would support the idea that we should use methanol over gasoline, which matches the environmentalists’ proposal. Your second statement is correct here, I think perhaps you may have misinterpreted what the environmentalists support. Hope this helps!