Consider Two Firms, a and B, That Must Engage in Pollution

Consider two firms, A and B, that must engage in pollution abatement. If Firm A has a lower marginal cost of pollution abatement than Firm B, then

A) regardless of costs, it is equitable for both firms to face the same direct controls on their pollution.
B) reallocating some of Firm B's abatement activity to Firm A can keep total abatement constant but reduce the total cost of abatement.
C) reallocating all abatement activity to Firm A will reduce pollution and reduce the total cost of abatement.
D) reallocating some of Firm A's abatement activity to Firm B will keep total abatement constant but will reduce the total cost of abatement.
E) Firm B should lower its costs.