classify the scenarios according to whether or not they describe a negative externality. a. a donut shop emits a delicious smell into the air as a by-product of production. b. a neighbor plays loud music that annoys the surrounding community. c. a person with no allergies gets a mosquito bite from a disease-free mosquito. d. a person gets a flu shot and is therefore less likely to spread illness to others. e. a factory emits pollution into the atmosphere as a by-product of production.