If the demand is perfectly elastic, buyers pay the entire tax

Which of the following is not an example of a barrier to entry?

a. Mighty Mitch's Mining Company owns a unique plot of land in Tanzania, under which lies the only large deposit of Tanzanite in the world. b. A chemist receives a patent for a new skin cream. c. An entrepreneur opens a cupcake bakery. d. A taxi cab driver in New York City obtains a license to legally provide transportation in New York City.

The profit-maximizing rule for a monopolistically competitive firm is to select the quantity at which

A) marginal revenue equals marginal cost. B) average revenue exceeds marginal cost by the greatest amount. C) price equals marginal cost. D) average revenue equals average total cost.