题目选项分析

Ethanol is a derivative of corn and other grains. When burned as fuel, it emits significantly lower levels of carbon monoxide, a major atmospheric pollutant, than does gasoline. For that reason, environmentalists claim that ethanol is a better source of energy than gasoline.

Which of the following, if true, most strongly supports the environmentalists' claim?

【选项】Ethanol can be used as heating fuel.