Refer to Figure 4-6. The amount of the excise tax I is

If Yt is I(2), then

A) ?2Yt is stationary. B) Yt has a unit autoregressive root. C) ?Yt is stationary. D) Yt is stationary.

A shift occurs in the supply curve for salt when:

a. the price of salt increases. b. improvements are made in the production process. c. salt is found to be associated with high blood pressure. d. consumers expect the price of salt to increase in the future.