The most people live in ________ economies and the fewest people live in ________ economies

The number of firms in an oligopolistic industry

A) must be less than 10. B) must be less than 20. C) must be small enough that firms are interdependent. D) must be large enough for firms to be independent.

One reason why firms in monopolistically competitive markets earn zero profit in the long run is because

a. product differentiation disappears b. barriers to entry become prohibitive c. the price elasticity of demand for each firm falls to zero d. so many firms enter the market that each firm's demand curve eventually becomes tangent to the firm's ATC curve e. each firm's ATC curve shifts upward to eventually become tangent to its demand curve