An externality is
a) a cost or benefit resulting from some activity or transaction that is imposed or bestowed on parties outside the activity or transaction
b) the total cost to society of producing an additional unit of a good or service
c) the amount a consumer pays to consume an additional amount of a particular good
d) a problem intrinsic to public goods: The good or service is so costly that its provision generally does not depend on whether or not any single person pays.
2) Which of the following is NOT a positive externality?
a) Scott studies diligently and his whole study group does better because of his added knowledge
b) Suzanne cooks dinner for herself and gives the leftovers to her roommates
c) Betty puts on makeup every day, and her classmates benefit by having a pretty girl to look at
d) Manuel brings candy bars to class and sells them for $0.25 more than he paid
e) Sharon lives next door to a doughnut shop and her house always smells wonderful.