Suppose there is a stock S in the market. The terminal price of S can be $40, $42, or $45. Therefore, we can describe the world in three states. There also exists a security has the

payoff as follows:

* When the terminal stock price of St is greater than $41, it pays St - $41.

* When the terminal stock price of St is equal to or less than $41, it pays 0.

Show that this security is a contingent claim.