An Important Reason That Direct Pollution Controls Are Usually Inefficient

An important reason that direct pollution controls are usually inefficient is that

A) different firms have different marginal costs of pollution abatement.
B) firms have little incentive to comply with them.
C) they generally garner little political support and thus eventually fail.
D) they create new pollution as they eliminate existing pollution.
E) it costs too much to make sure that firms comply with the regulations.