Which of the Following Statements Is True of a Monopoly

Which of the following statements is true of a monopoly cost curve?

A) Monopoly costs to market share curve is more s-shaped than network externality returns to market share curve.
B) The steepness of the monopoly cost curve is largely a function of a firm's discretionary behavior.
C) It is not possible for a network externality returns curve to cross a monopoly cost curve.
D) A firm choosing to exploit its monopoly power is flattening its monopoly costs curve.