Each of Davisson's production managers (annual salary cost, $45,000) can oversee 60,000 machine hours of manufacturing activity. Thus, if the company has 50,000 hours of manufacturing activity, one manager is needed; for 75,000 hours, two managers are needed; for 125,000 hours, three managers are needed; and so forth. Davisson's salary cost can best be described as a: variable cost.

semivariable cost.

step-variable cost.

fixed cost.

step-fixed cost.