Marginal external benefit is​ _______.
A. the benefit from a good or service that someone other than the consumer of that good or service receives
B. the marginal benefit enjoyed by everyone who receives a benefit from the good or service
C. the benefit from an additional unit of a good or service that the consumer of that good or service receives
D. the benefit from an additional unit of a good or service that people other than the consumer of that good or service receives