Consider an American put option that is 12 months from expiration. The current value of the underlying is 60, and volatility is 15% per year. Contruct a 3-step recombining (d = 1/u) binomial tree to price this option. 15. What is the size of an up move: (a) 1.0779; (b) 1.1634; (c) 0.9935; (d) 1.0905; This next question is DOUBLE weight. Please fill out 16 and 17 with the same answer. 16.-17. If the risk neutral probability of an up move is 0.5169, what is the risk free interest rate: (a) 1.50%; (b) 2.0%; (c) 3%; (d) 4.0%