27.3 Externalities Definitions For the examples below, identify whether it is an example of a positive externality, a negative externality, or neither. Explain your answer. (a) Two students talk to one another during an economics lecture, and a third student is distracted and misses the definition of Externality. (b) An astroid hits the earth, destroying multiple cities. (c) A world power invests in a Planetary Defense Program that can eliminate asteroids before they hit the earth. (d) A bookstore pays the cost of maintaining a cozy store environment, stocking a wide selection of books, and hiring well-trained and knowledgeable staff. Potential customers frequently visit the bookstore and then order the book on Amazon