If the market price is $25 in a perfectly competitive market, the marginal revenue from selling the fifth unit is

When money supply __________, the real rate of interest __________

A) increases; falls B) increases; rises C) decreases; rises D) increases; remains unchanged

The largest budgetary expense for the federal government in 2011 was

a. interest on the national debt. b. health. c. highways. d. income security.