What Is the Meaning of the Phrase "Dilemma of Regulation

What is the meaning of the phrase "dilemma of regulation"?

A) Natural monopolies achieve economies of scale but charge high prices when there is no government regulation; government regulation reduces prices but results in diseconomies of scale.
B) Natural monopolies are profitable, but only if the government permits price discrimination; government regulation to restrict price discrimination reduces monopoly prices, but the regulation also reduces monopoly output.
C) The fair-return price achieves allocative efficiency but may produce economic losses; the socially optimal price yields a normal profit but may not be allocatively efficient.
D) The socially optimal price achieves allocative efficiency but may produce economic losses; the fair-return price yields a normal profit but may not be allocatively efficient.