Suppose That the Economy Is at Full Employment, the Price

Suppose that the economy is at full employment, the price level is 100, and the multiplier is 2.Investment increases by $100 billion.In the short run, the price level _______ because _______.

A) falls; investment only increases as the price level falls
B) remains at 100; the economy initially moves to an above full- employment equilibrium.To return to full employment, aggregate demand decreases
C) rises; the economy returns to full employment
D) remains at 100; the aggregate demand curve shifts horizontally, which keeps the price level constant
E) rises; the short- run aggregate supply curve is upward sloping