Given below is information on a 4-sector economy. All figures given are in RM (Million).

Table 1.0: The Spending in a Country Consumption expenditure (C) = 150 + 0.8Yd Investment expenditure (1) = 100 Government expenditure (G) = 200 Taxes (T) = 100 Import (M) = 200 Export (X) = 450 a) Derive the saving function and calculate the marginal propensity to save (MPS). (4 marks) b) Calculate the national income equilibrium for 4 -sector economy using Aggregate Demand -Aggregate Supply (AD - AS) approach and Leakages - Injection approach. (6 marks) c) Define an open economy. (1 mark) d) Explain circular flow of income for 4-sector economy. (4marks)