Suppose That a Monopoly in the Market for an HIV

Suppose that a monopoly in the market for an HIV drug becomes competitive after another company develops a different formula with the same efficacy. What is likely to happen to prices and quantity in this market?

A) Both prices and quantity would rise.
B) Prices would rise, but quantity would fall.
C) Prices would fall, but quantity would rise.
D) Both prices and quantity would fall.