Correct Response: A. Catalytic converters catalyze the reactions of toxic emissions, such as CO, into more benign compounds such as CO2. Smokestack scrubbers (B) are used to “wash out” particulate and other contaminants from smokestack emissions through the introduction of a washing compound. They are not used primarily to reduce CO emissions. Carbon offsets (C) are a market- based mechanism for companies to offset the amount of greenhouse gasses they emit by investing in projects that reduce greenhouse gas emissions. CO is not considered to be a major greenhouse gas. Coal gasification (D) is a method of processing coal to create a variety of fuels and other products. It has nothing to do with reducing CO emissions, and it is in fact a source of CO.
