Kenneth Chay and Michael Greenstone Examined the Impact of Reductions

Kenneth Chay and Michael Greenstone examined the impact of reductions in air pollution since the passage of the Clean Air Act of 1970.Which of the following statements summarizes their findings?

A) The marginal benefit of reductions in air pollution was less than the marginal cost.
B) The marginal cost of reducing emissions of sulfur dioxide has increased over time as the marginal benefit of the reductions has increased.
C) The benefits of reducing the six main air pollutants in the two years following the Act greatly exceeded the costs.
D) In the two years following passage of the Act, fewer infants died than would have died if the Act had not been passed.