The Diagram Below Shows the Demand Curve Facing a Single-Price

The diagram below shows the demand curve facing a single-price monopolist. FIGURE 10-4
-Refer to Figure 10-4.Suppose the firm is currently at point C on the demand curve,selling 300 units at $40 per unit.If the firm moves to point D,the revenue the firm gives up on the units it was already selling is ________ and the revenue it gains on the additional units sold is ________.

A) $9000; $9000
B) $12 000; $12 000
C) $3000; 4000
D) $4000; $3000
E) $3000; $3000