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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.