Answer:
B. Positive externality
Step-by-step explanation:
An externality is a benefit or a detriment to a third party created by the production or consumption of goods or services. A third party is everybody else other than the producer or consumer of a product. An externality is either positive or negative.
A positive externality is when consumption or production creates a benefit to a third party. The third-party does not meet the cost of products but indirectly enjoys its production.