For parts (a), (b), and (c), consider the thre e-p erio d binomial tree of sto ck price s with the sp ot price 100, u = 1.25, and d = 0.8. Assume zero interest rates and dividends. (a) Find the time-zero value of an ATM European call option that expires at the end of three periods. (b) Suppose the stock price follows the following path: 100, 80, 100, 125. Describe the replicating portfolio and all the adjustments until the expiry. (c) Find the time-zero value of a look back option that pays at expiration the maximum minus the initial stock price.