Consider a closed economy model where consumption spending is given by C = A+ bY^d, disposable income Y^d = Y - T - tY, where Y is output, T is lump-sum taxes, t is the proportional tax rate and b is the marginal propensity to consume. Planned investment is given by I^P and government spending is G. Planned investment andgovernment spending do not depend on Y. Suppose A = 100, b = 0.8, T = 50, t = 0.5,I^P = 100 and G = 140. The multiplier is equal to: a. 1/(1-b-t) b. 5 c. G/ (1-b(1-t)) d. 2 e. 1.67