Traffic congestion causes higher costs and discomfort to residents of a city, and: a. the marginal social cost of any one individual's use of the roads is less than the individual marginal cost. b. the marginal social cost of any one individual's use of the roads is greater than the individual marginal cost. C. the marginal social cost of any one individual's use of the roads equals the individual marginal cost. d. the marginal social cost of any one individual's use of the roads equals the individual marginal benefit. C. the marginal social cost of any one individual's use of the roads is less than the individual marginal benefit.