Assume that the position of a nation’s aggregate demand curve has not changed, but the long-run equilibrium price level has declined. Other things being equal, which of the following factors might account for this event? (See page 232.)
a. An increase in labor productivity
b. A decrease in the capital stock
c. A decrease in the quantity of money in circulation
d. The discovery of new mineral resources used to produce various goods
e. A technological improvement