Answer: The bees can fertilize the apple orchards.
Explanation: Externality means the cost or benefit that a unrelated party incurs because of a decision. In the give case, the bees can help to fertilize the orchards in the neighborhood leading to more fruit in those orchards.
In this case the owner of that apple orchard is unrelated to the decision of the beekeeper moving to the neighborhood but still he or she will benefit from it.
