单选题 Which of the following statements regarding economic costs is most accurate?

A. Sunk costs involve setting aside payments to retire long-term debt.
B. In the long run, expected average marginal cost is the most relevant cost to the firm.
C. Fixed costs are not a consideration in the short run operating decision, but must be considered in the long run.

【正确答案】 C

【答案解析】In the short run, the decision to operate is based on whether price covers average variable costs. In the long run, average fixed costs must be considered as well. Sunk costs are historical costs. Sinking funds are established to retire long-term debt. The marginal revenue from selling an additional unit of output must be at least as great as its marginal cost of production.