The Per-Week Demand for Use of the Golden Gate Bridge

Multiple Choice

The per-week demand for use of the Golden Gate Bridge in San Francisco is P = 13 - 0.15Q during peak traffic periods and P = 7 - 0.1Q during off-peak hours,where Q is the number of cars crossing the bridge in thousands and P is the toll in dollars.If the marginal congestion cost of using the bridge is MC = 5 + 0.2Q,what is the optimal off-peak load toll for crossing the bridge?

A) 6.5.
B) 8.0.
C) 8.7.
D) 9.9.
E) 10.6.