Final answer:
A monopolistic competitor faces a downward-sloping demand curve and a downward-sloping marginal revenue curve. If price makers raise their prices, they will lose profit.
Step-by-step explanation:
A monopolistic competitor faces a downward-sloping demand curve and a downward-sloping marginal revenue curve because of the presence of substitutes. Unlike a monopoly, a monopolistic competitor can raise its prices without losing all of its customers, but it will lose more customers than a perfectly competitive firm. Therefore, if price makers raise their prices, they will lose profit.