For something to satisfy the medium-of-exchange function of money, it must be

Much of the nation's coal is extracted by strip mining. This process leaves a huge barren hole in the ground when complete, and the cost of replanting the trees is approximately $10 per ton of coal. Burning the coal for electricity causes air pollution. No one knows how much damage the air pollution causes, but we know that for another $10 per ton the power plant can be outfitted with a pollution

control device. What is one measure of the true social cost of coal fired electricity, in dollars per ton? a. Private marginal cost plus the $10 replanting charge. b. Private marginal cost plus the $10 emission control charge. c. Only the $20 of replanting and emission control charges, because the other costs are private, not social. d. Private marginal cost plus the $20 of replanting and emission control charges. e. In order to answer this question we need to know the dollar value of the pollution.

"There is no such thing as a free lunch." This statement best reflects the fact that

a. consumers are unwilling to pay for a good unless it provides them with value. b. an opportunity cost is always present when scarce resources are used to produce a good. c. it generally requires enormous effort to search out the best place to eat lunch. d. the value of a good to consumers will decrease as they have more of it.