A negative externality:

A. is any cost above the economic cost.
B. equals the social cost plus the firm's private cost.
C. is an uncompensated cost imposed by an individual or firm on others.
D. equals the opportunity cost minus the social costs.

C. is an uncompensated cost imposed by an individual or firm on others.

Explanation:

Negative externalities can include damage to the environment, health complications (and medical bills) later on, etc. For example, the cost involved with treating lung disease would be a negative externality with cigarettes.

I hoped this helps!

answer; fair labor and standard act;