Use the Following to Answer Question

Multiple Choice

Use the following to answer question:
Figure: The Optimal Quantity of Pollution
-(Figure: The Optimal Quantity of Pollution) The figure The Optimal Quantity of Pollution shows the marginal social cost (MSC) and marginal social benefit (MSB) for firms that pollute the air with sulfur dioxide. Using the figure, the optimal Pigouvian tax per unit of pollution is:

A) $500.
B) $250.
C) $167.
D) $83.