Are externalities positive or negative? Give an example. Externalities ________. A. can be negative or positive. Logging creates a negative externality, and education has a positive externality B. are always negative, and an example is the pollution created by trucks C. are always positive, and an example is flu vaccinations D. can be negative or positive. A negative externality is having to go to school when you would rather go to the beach and a positive externality is spending time with your friends