Robinson's utility is given by U(C1, C2) = In C1 + In C2 Budget constraints are given by C+B = Y C2 = Yo+ B for period 1 and 2 respectively. We assume interest rate is zero (r = ()). 1) Derive the present value budget constraint. 2) Solve the utility maximization problem and derive the optimal level of consumption for each period, C, and C2 3) Suppose Robinson can not borrow. Namely, B 2 0. What is the optimal level of consumption for each period C, and Ca. To answer this, consider the following two cases for the optimal level of consumption i) Y1 2 12 ii) Y1