One of the reasons why the aggregate demand (AD) curve slopes downward is that

Group of answer choices

a) aggregate expenditure increases as the price level rises.

b) decreases in the price level cause increases in private-sector wealth which lead to increases in desired consumption.

c) increased production results in lower production costs.

d) when the price level falls firms must be more competitive when output increases.

e) when the price level falls consumers increase their saving rate.