The answer is: b. Monopolistic competition. Since products in a monopolistic competition are slightly different from each other, advertising and promotional activities are used to help inform buyers about the differences in quality of product.

a. Perfect competition.

False, in a perfect competition there is no differentiation in product so product differentiation and advertising are not as beneficial.

c. Oligopoly.

False, in an oligopoly the market defines your advantage, not product differentiation activity. Promotional activity may be beneficial.

d. Monopoly.

False, in a monopoly the market defines your advantage, not product differentiation or promotional activity.