When interest rates fall in the United States (with the price level fixed), the value of the dollar ________, domestic goods become ________ expensive, and net exports ________

If the social cost of producing a good or service exceeds the private cost

A) the sum of consumer surplus and producer surplus is maximized. B) a positive externality exists. C) the market achieves economic efficiency. D) a negative externality exists.

If expectations are formed rationally, then individuals

A) will have a forecast that is 100% accurate all of the time. B) change their forecast when faced with new information. C) use only the information from past data on a single variable to form their forecast. D) have forecast errors that are persistently low.