Suppose the current price of the S&R index is 800 and the continuously compounded risk-free rate is 5%. A 1 -year $815-strike European call costs $75 and a 1 -year $815-strike European put costs $45. Consider the strategy of buying the stock, selling the $815-strike call, and buying the $815-strike put. (a) What is the payoff on this position held until the expiration of the options? (b) What is the arbitrage implied by your answer to (a)? (c) What difference between the call and put prices would eliminate arbitrage? (d) What difference between the call and put prices eliminates arbitrage for strike prices of $780, $800, $820, and $840?