Suppose that a pure monopolist can sell 20 units of output at $10 per unit and 21 units at $9.75 per unit. The marginal revenue of the 21st unit of output is

A) $9.75.
B) $204.75
C) $4.75.
D) $0.25.

Marginal Revenue

The additional income earned from selling one more unit of a good or service.

Output

The volume of output in terms of products or services from a business, sector, or country within a designated timeframe.

Units

Units are standard measures or quantities used to specify or quantify the dimensions, amount, or capacity of something.