In the graphs, the numbers in parentheses near the AD1, AD2, and AD3 labels indicate the level of investment spending associated with each curve. All figures are in billions. The economy is at point Y on the investment demand curve. Given these conditions, what policy should the Fed pursue to achieve a noninflationary, full-employment level of real GDP?
A) increase aggregate demand from AD3 to AD2.
B) decrease the money supply from $225 to $150 billion.
C) increase interest rates from 4 to 8 percent.
D) make no change in monetary policy.