If the LRATC curve is falling. then O diseconomies of scale are present. O the law of diminishing marginal returns is operating. constant returns to scale are present. O economies of scale are present. D Question 18 4 pts Implicit cost is a O sunk cost. cost that represents the value of resources used in production for which no monetary payment is made. cost incurred in the past that cannot be changed by current decisions and therefore cannot be recovered. O cost that is incurred when a monetary payment is made. D Question 19 4 pts In the long run, 3 costs can be fixed or variable. there are no variable costs, all costs are fixed costs. @ all costs are variable costs