Monopolies are inefficient because they (i) eliminate barriers to entry. (ii) price their product at a level where marginal revenue exceeds marginal cost. (iii) restrict output below the socially efficient level of production. a. (i) and (ii) only b. (ii) and (iiii) only d. (i), (ii), and (iii)

Monopolies are known for their significant market power, which allows them to set prices higher and restrict production. This causes them to operate at levels where their marginal revenue is less than the marginal cost, leading to an overall inefficiency in resource allocation. On the other hand, historically, monopolies like the Standard Oil Company in the late 19th century monopolized entire markets, demonstrating how they can stifle competition and innovation, ultimately harming consumers by creating a lack of choice and higher prices.