3. Suppose there are two assets traded in the financial market. One is risky and the other is risk-free. The price of the risky asset at period 0 is set to be $S. The price of the risky asset at period 1 will be $(1 + u)s, with probability of p and $ 1.5, with probability of (1-P) in the next period. On the other hand, for $1 investment the risk-free asset will return $1 in the next period. Of course, it is assumed that u > 0. (a) A one-period put option with strike price $K is introduced. Find its arbitrage-free price of the put option if So