A stock is currently trading at $100. In each month, the stock will either increase in price by a factor of u=1.10 or fall by a factor of d=0.90. The risk-free rate of interest per year is 2%. What is the price of a $100-strike price, two-month American put option? Note that exp(0.02×1/12) = 1.0017. (a) $5.038 (b) $5.078 (c) $5.158 (d) $5.198 (e) $5.268