(Figure: Market 8) Use the Graph to Answer the Question

Multiple Choice

(Figure: Market 8) Use the graph to answer the question.
The graph shows the marginal social cost, marginal private cost, and demand curves in the aux cable market. If the government uses a quota to control an externality in this market, what quantity would be chosen as a limit on sales?

A) two
B) four
C) six
D) 12