If a Single-Price Monopoly Is Making a Large Economic Profit,what

Multiple Choice

If a single-price monopoly is making a large economic profit,what keeps other firms from competing away the profit?

A) There are barriers to entry.
B) The monopoly must be keeping the amount earned secret.
C) The market must be too small.
D) The existing firm's ATC must be too large to allow competitors to enter and earn an economic profit.
E) Nothing, other firms will enter and will compete away the profit.