Some coal is mined by private companies on land owned by the federal government. Two economists writing in an opinion column argue, "The federal government should also take into account the economic consequences of burning coal when pricing this fuel. The price for taxpayer-owned coal should reflect, in some measure, the added costs associated with the impacts of greenhouse gas emissions." Source: David J. Hayes and James H. Stock, "The Real Cost of Coal," New York Times, March 24, 2015. Part 2 a. By "the added costs associated with the impacts of greenhouse gas emissions," the economists mean the A. total private cost of burning coal. B. external costs (negative externalities) such as global warming and health effects of pollution. C. costs of controlling pollutants for the coal producers. D. costs of controlling pollutants for the coal burning producers