Those Opposed to Fracking, a Method of Extracting Natural Gas

Multiple Choice

Those opposed to fracking, a method of extracting natural gas through breaking up underground rocks with chemicals and water, warn that this method might pollute nearby sources of drinking water.
-If this pollution occurs, the marginal social cost equals the

A) marginal external cost.
B) private marginal cost.
C) sum of the private marginal cost and the marginal external cost.
D) private marginal cost minus the marginal external cost.