Which of the following statements is true?

A) The total cost of production in a perfectly competitive market can be minimized only when the marginal costs across firms in the market are different.
B) When a competitive market is allowed to operate efficiently, firms end up producing goods using the least amount of scarce resources.
C) Under a perfectly competitive framework, a ruling authority is essentially required to dictate goals for the betterment of society.
D) A firm interested in maximizing profits in a perfectly competitive market will produce output at a level where marginal revenue is equal to the price and greater than the marginal cost.

B