The AD curve is downward sloping because

a.The equilibrium level of GDP in the Aggregate Expenditure model increases as autonomous consumption increases.

b.The equilibrium level of GDP in the Aggregate Expenditure model decreases as the price level increases.

c.The equilibrium level of GDP in the Aggregate Expenditure model increases as the price level increases.

d.The equilibrium level of GDP in the Aggregate Expenditure model increases as planned investment increases.