To encourage the production of honey, several beekeepers place their beehives in a farmer's orchards and fields. As the bees gather nectar to make money, they pollinate the orchards and fields, thereby increasing the yields of the fruit and grain crops. This arrangement results in?
A. a positive externality that benefits the farmer.
B. no significant additional benefit to anyone.
C. a positive externality that benefits the consumer.
D. a negative externality for which the farmer should be compensated.