Question

the short run is a period of time: a. that is long enough to permit changes in the firms plant size. b. in which production occurs within six months. c. in which a firm uses at least one fixed input. d. in which production occurs within one year.

Explanation:

The short run in economics is defined by the presence of at least one fixed input (like factory space or heavy machinery) that a firm cannot adjust, while variable inputs (like labor, raw materials) can be changed. Options a describes the long run, where plant size can be altered. Options b and d are incorrect because the short run is not defined by a specific calendar time frame, as it varies by industry and firm.

Answer:

c. in which a firm uses at least one fixed input.