A stock index is currently 1,000. Its volatility is 20%. The risk-free rate is 5% per annum

(continuously compounded) for all maturities and the dividend yield on the index is

3%. Calculate values for u, d, and p when a six-month time step is used. What is the

value a 12-month American put option with a strike price of 980 given by a two-step

binomial tree.