a. the terms social cost and external cost are synonyms. b. social cost is the sum of private and external costs. c. when the production of a good results in pollution, private and social costs are the same. d. when the production of a good results in pollution, private and social costs are different. e. pollution is an example of an external cost. f. wages are an example of an external cost. g. private costs are costs that the firm is not obligated to disclose to the public.