In which of the following market structures is product differentiation always present?AOligopoly.BPerfect competition.CMonopolistic competition.

The market structure where product differentiation is always present is Monopolistic competition.

Here's why:

A. Oligopoly: In an oligopoly, there are only a few firms that make up an industry. This select group of firms has control over the price and, like a monopoly, an oligopoly has high barriers to entry. The products that the oligopolistic firms produce are often nearly identical and, therefore, the firms are often competing on the basis of price, service, and marketing.

B. Perfect competition: In a perfectly competitive market, all companies sell identical products, there's no possibility for a company to differentiate its product.

C. Monopolistic competition: In a monopolistic competitive market, every company makes a product that is slightly different from its competitors. Product differentiation is the main characteristic of this type of competition. Therefore, every company has a mini-monopoly in its specific product.