What is a positive externality?(1 point) Positive externalities occur when a service is available without cost. Positive externalities occur when a service is available without cost. Positive externalities occur whenever there is a private benefit to a good or service. Positive externalities occur whenever there is a private benefit to a good or service. Positive externalities occur when there is both a social benefit and private benefit from a good or service. Positive externalities occur when there is both a social benefit and private benefit from a good or service. Positive externalities occur whenever there is a social benefit to a good or service.