A **one** year European-style **put** option has a strike price of $**4**. The option's underlying stock pays no dividends and currently trades at $**5**. The risk-free interest rate is **10**% pa continuously compounded. Use a **single** step binomial tree to calculate the option price, assuming that the price could rise to $**8** ##(u = 1.6)## or fall to $**3.125** ##(d = 1/1.6)## in one year. The put option price now is: