Refer to the Following Figure

Multiple Choice

Refer to the following figure:

The above graph shows the demand and cost conditions facing a price-setting firm.
-When output is 50 units, what will happen to total revenue if the firm sells another unit of output?

A) Total revenue will increase $13.50.
B) Total revenue will increase $11.00.
C) Total revenue will increase $9.00.
D) Total revenue will increase $6.00.
E) none of the above