Because trucking as an industry involves the generation of pollutants in engine exhaust,

A) the supply curve of trucking services overstates the true cost of providing those services.
B) the supply curve of trucking services understates the true cost of providing those services.
C) the demand curve for trucking services overstates the true benefit of providing those services.
D) the demand curve for trucking services understates the true benefit of providing those services.
E) the market for trucking services will always be away from equilibrium by an amount equal to the value of the externality.

B