A reliable indicator of a healthy economy is a stable currency

All of the following are examples of government purchases except

a. F-15 fighter planes b. food and clothing for the armed forces c. interstate highways d. post offices e. the Washington D.C. residence of Illinois Senator Richard Durbin

The price of tradable emission permits for sulfur dioxide

A. remained almost totally unchanged since 1992. B. has steadily decreased since 1992. C. was set at a specific price in 1992 and cannot change without a new law. D. has steadily increased since 1992.