Economic analysis requires both mathematical reasoning and historical study

For a perfectly competitive firm, when MC is less than MR

A) the producer has an incentive to expand output. B) the producer has an incentive to decrease output. C) the producer has no incentive to change production. D) economic profits must be positive.

Which of the following provides the most secure protection for a firm with monopoly power?

a. quality advertising b. legal barriers restricting entry into the market of the monopolist c. predatory pricing d. limited economies of scale