Which of the following reasons helps explain why the aggregate demand curve is downward sloping?

a. The real balances effect or wealth effect: Consumers spend more on goods and services when the price level falls because lower prices increase consumer purchasing power.
b. The producer-push effect: At less than full employment, increases in quantity demanded will raise price, and thus will motivate sellers to produce more.
c. The hidden inflation effect: As the price level rises, consumers fail to recognize that prices are higher, and consequently they fail to reduce expenditures on goods and services.
d. None of the above.

a