Which of the following generate the type of externality previously described? (Negative Externality)
A) Gilberto has planted several trees in his backyard that increase the beauty of the neighborhood, especially during the fall foliage season.
B) The local airport has doubled the number of runways, causing additional noise pollution for the surrounding residents.
C) A microbiology lab has published its breakthrough in swine flu research.
D) Your roommate Cho has bought a cat to which you are allergic.

B. The local airport has doubled the number of runways, causing additional noise pollution for the surrounding residents.

Explanation:

A negative externality occurs when the production or consumption of a good causes a negative effect to a third party. It is a secondary effect of an economic activity which besides, it's not reflected in the profit or direct costs of that activity.

Some examples of negative externalities are: loud music, pollution, vehicular congestion or building new roads.

the amount of money you earn by working is your income.

the percentage of people actively looking for a job is called unemployment.