What is demonstrated by the positive slope of a marginal cost curve for pollution abatement?
◦ Additional increments of pollution abatement will yield decreasing benefits.
◦ It is impossible to know the benefits from additional increments of pollution reduction.
◦ The marginal benefit of pollution reduction will increase with additional increments of pollution reduction.
◦ The cost of an extra unit of pollution abatement will increase as the total amount of abatement rises.
◦ Society views additional increments of pollution reduction as absolutely necessary.