The Optimal Amount of Pollution Abatement Is Such That

The optimal amount of pollution abatement is such that

A) there is no remaining pollution.
B) the total benefit of reducing pollution is equal to the total cost of reducing pollution.
C) the marginal social cost of reducing pollution is just equal to the marginal social benefits from doing so.
D) the marginal private cost of reducing pollution is just equal to the profit of the polluting firms.
E) none of the above; there is no optimal amount of pollution abatement.