Which Statement Best Characterizes Why an Aggregate Demand Curve Slopes

Multiple Choice

Which statement best characterizes why an aggregate demand curve slopes downward?  

A)  because a decrease in the price level decreases the real value of household wealth 
B)  because a decrease in the domestic price level increases imports 
C)  because an increase in the price level leads to a decrease in demand for money, which decreases interest rates 
D)  because a decrease in the domestic price level increases exports