If unintended harm to environment is part of unintended harm to society, then if a price reflects unintended harm to society, it must also reflect unintended harm to the environment. (Think about “harm to environment” as a subset completely contained within a larger set of “harm to society.”)

Externalities are defined as unintended but harmful consequences to society. But we don’t know whether harm to the environment is part of harm to society. So (B) doesn’t make the argument valid; we’d still have no way of knowing whether sound management requires that a price reflect harm to the environment.

Whether it’s possible to accurately and completely predict the effects of using a resource when setting a price tells us nothing about whether harm to the environment is part of harm to society. Without a connection between environmental harm and societal harm, we have no way of knowing whether sound management requires that a price reflect harm to the environment.

(D) establishes that sound management requires that externalities are precisely assessed. But does having a price reflect externalities imply having a price that reflects harm to the environment? We don’t know.

Whether a resource should be used is separate from what’s required for sound management of a resource. In addition, (E) tells us nothing about the relationship between harm to the environment and harm to society.