Put-call parity holds only for European options. For American options on a non-dividend- paying stock, prove the following result: S, -K SC-PSS, - Ke=. hints: please follow the proof of the put-call parity for European options to construct a portfolio of four positions, and then analyze two possible outcomes: (1) If the short party decides to exercise American put/call earlier at t; (2) If the short party decides to exercise American put/call at maturity T. So-K-C+ PK If ST