People maximize utility when they make the choices that provide the highest level of satisfaction

One difficulty in using voluntary transactions to internalize externalities is that

A) people are motivated by self-interest and are often unwilling to engage in a transaction that might make another person better off. B) the government usually will not enforce contracts of this type. C) transaction costs of coming to an agreement can be very large when numerous people are involved. D) people usually don't understand what the real opportunity costs are that they face.

If long-run average total cost decreases as output increases, this is due to:

A. Declining average fixed costs B. The law of diminishing returns C. Economies of scale D. Externalities