14. Costs of production that change with the rate of output are: (a) Long-run costs. (b) Fixed costs. (c) Implicit costs. (d) Variable costs. 15. For which of the following costs would the cost curve appear as strictly downward-sloping curve? (a) Average total costs. (b) Average variable costs. (c) Marginal costs. (d) Average fixed costs. 16. The marginal cost curve intersects the minimum of the curve representing: (a) ATC. (b) TC. C) AFC. (d) All of the above. 17. Which of the following is equivalent to ATC? (a) AFC - AVC. b) (FC + VC)/Q. c) Change in total cost divided by change in output. d) None of the above. 18. In the long run, a firm: (a) Is committed to a particular scale of operations. (b) Has both fixed and variable costs. c) Has no fixed costs; all costs are variable. (d) Has no variable costs; all costs are fixed. 19. the unit labor cost is: When labor produces 5 units of output per hour for a wage rate of $10 per hour, (a) $20 per hour. (b) $2 per unit. (c) $.50 per hour. (d) $.50 per unit. 20 If a firm has $250 in explicit cost, $150 in implicit costs, and sells 100 units for $5 each then accounting profit would be: (a) $100. (b) $250. (c) $350. (d) $500