Consider a put option on ITK Corp's common stock. The current ITK Corp stock price is $1,000 and it is expected to either increase by 25% or decrease by 20% each half year with equal probability. The option has a strike price of $1200, an expiration time 18-month from now and the underlying asset of each option is one unit of TTK Corp's common stock. In additional to the standard exercising right for the put buyer at maturity, this option has a special clause that gives the buyer an additional right to exercise the option 6-month from now. The risk-free interest rate is 1% per annum and the stock is not expected to pay any dividend over the next 3 years. a) Use a three-period binomial model to calculate the current value of the put option. (12 marks)