If the equilibrium level of real GDP is $100,000 below the full-employment level of real GDP and the spending multiplier is 4, how much of an increase in autonomous aggregate expenditures (such as government spending) is required to move the equilibrium to the full-employment level of real GDP?
a. $400,000.
b. $200,000.
c. $100,000.
d. $25,000.
e. $10,000.