Exercise 4.1. In the three-period model of Figure 1.2.2 of Chapter 1, let the interest rate be r= so the risk-neutral probabilities are p=q= . (i) Determine the price at time zero, denoted V., of the American put that expires at time three and has intrinsic value gp(s) = (4 - 8). (ii) Determine the price at time zero, denoted V., of the American call that expires at time three and has intrinsic value gc(s) = (s - 4)+. (iii) Determine the price at time zero, denoted VS, of the American straddle that expires at time three and has intrinsic value 9s(s) = 9P(8) + 9c(s). (iv) Explain why V