Answer
d) 3600 dollars
Work Step by Step
Government increases purchases by 1200
marginal propensity to consume is 2/3
multiplier = 1/(1-marginal propensity to consume)
multiplier = 1/(1-2/3)
multiplier = 1/(1/3)
multiplier = 1/ (1/3)
multiplier = 3
1200*3 = 3600