The short run is defined as A. a period of time of five years or less. B. the period of time in which all factors of production are variable. C. the period of time in which at least one factor of production is fixed. D. the period of time it takes the firm to make its first economic profit.]

C. the period of time in which at least one factor of production is fixed.

Explanation:

The short-run is a condition, were some controls and market are not in fair equilibrium, some factors like the variables and other that are foxed have limited entry or exit to the industry.  In the macroeconomics a long run is a time when the general price, and contractual wage rates, along with the expectations are adjusted entirely to the states of the economy. and this contrast to the short-run where the variable is not fully fixed or adjusted. The short-run for a firm will increase the production of the marginal costs is less than the marginal revenue. The transition from the short to the long-run market equilibrium may be done on considering the supply and demands.