In a model with a constant price level and demand-determined output, a downward shift of the saving function causes equilibrium national income to... a. Remain constant but consist of more consumption and less investment. R O b. Remain constant because it does not affect desired aggregate expenditure. O c. Rise because the AE function shifts upward simultaneously. O d. Remain constant but consist of less consumption and more investment. Oe. Fall because the AE function shifts downward simultaneously