Assume Someone Organises All Farms in the Nation into a Single-Price

Assume someone organises all farms in the nation into a single-price monopoly. What is the monopoly's marginal revenue curve?

A) It is a line that lies above the new monopoly's demand curve.
B) It is a vertical line at the monopoly's chosen output level.
C) It is a horizontal line at the competitive industry's price.
D) It is a line that lies below the new monopoly's demand curve.
E) It is identical to the demand curve for the monopolist's output.