The largest component of aggregate income is:

Which of the following sets of goods might, under the right circumstances, be substitutes for water?

A) Milk and juice B) Beer and wine C) Stones and bricks D) A, B, and C above are all potential substitutes for water. E) A and B above are potential substitutes for water, but C (stones and bricks) can never be substitutes for water in the real world.

The marginal social cost of producing a good or service is the

A) cost of producing an additional unit borne by the producer. B) cost of producing an additional unit borne by people other than the producer. C) sum of the marginal private cost and the marginal external cost. D) same as marginal external cost. E) sum of the marginal private cost and the marginal external cost minus the marginal social benefit.