Assume the price of a tradable emissions permit for a ton of sulfur dioxide is $150. Which of the following is incorrect?Choose one answer.a. A firm that has more permits than it plans to use has an incentive to limit pollution up to the point at which the marginal benefit of emissions is equal to $150.b. The opportunity cost of emitting a ton of sulfur dioxide is $75 for all firms.c. A firm that buys permits has an incentive to limit pollution up to the point at which the marginal benefit of emissions is equal to $150.d. The opportunity cost of emitting a ton of sulfur dioxide is $150 for all firms.