Consider the following macroeconomic model under "slack" conditions: Y = C+I+G C = 800 + (2/3) YD YD = Y- TX + TR TX = 200+ (1/4) Y TR = 0 I = 200 G = 900 where Y = real income, C = real consumption, I = real investment, G = real government expenditures, YD = real disposable income, TX = real tax revenue, and TR = real transfer payments. (All figures in billions of U.S. dollars.) allob lupe no 28) The equilibrium level of output (income) in this economy is; a) $3533.33 billion b) $2735.25 billion c) $4333.33 billion d) $5500 billion