A stock price is currently selling at $50. Over each of the next two 3-month periods it is expected to go up by 5% or down by 5%. The risk-free interest rate for each of these three months is 2%. Let d be a financial derivative with payoff function f(ST, K) =A|S, - K], with |. | denoting the absolute value. (a) Use a two-step tree to compute the parameter 6 as a function of the strike price K if the initial cost/premium of the financial derivative d at time 0 is do = $3