This chapter discusses many types of costs: opportunity cost, explicit costs, fixed cost, variable cost, average fixed cost, and average variable cost. Fill in the type of cost that best completes each sentence In a pizza industry, the cost of the factory is a(n) fixed cost only in the short run but not in the long run. is always falling as the quantity of output increases. A cost that depends on the quantity produced is a(n) variable cost . The term opportunity cost refers to all the things you must give up for taking some action. The term refers to costs that involve direct monetary payment by the firm. is falling when marginal cost is below it and rising when marginal cost is above it.