Consider a put option on the Sinopec stock in the following 1-step binomial model. Suppose the strike price = K, with Pup>K>Pdown The interest rate over the 1-step period is r. (a) What is the fair present price of such a put option? future worth of the put option in "up" scenario stock put option Pup Pnow Present worth of put option (l.e. price of the put option) (1-9) (1-9) Pdown ? future worth of the put option in "down" scenario (b) Compute the corresponding risk-neutral probability