4. Answer all parts of this question. a) Explain why individuals may try smooth their consumption over their lifetime. Illustrate this concept with a diagram. (3 marks) b) Explain how borrowing constraints can impede the process of consumption smoothing. If many households are affected by such constraints, explain how this may result in a "Keynesian" consumption function. (3 marks) c) In a closed economy Keynesian Cross framework, show how a decline in investment will lead to a fall in income. Explain the role of the consumption function and the multiplier in this process. (8 marks)