In a collusive oligopoly, joint profits are maximized when a price is set based on ______.

a. The intersection of the marginal revenue curve and the average total cost curve

b. The intersection of the marginal revenue curve (derived from the market demand curve) and the horizontal sum of the short-run marginal cost curves for the oligopolists

c. Both the intersection of the marginal revenue curve and the average total cost curve and the intersection of the marginal revenue curve (derived from the market demand curve) and the horizontal sum of the short-run marginal cost curves for the oligopolists

d. None of these