4. A long butterfly spread with calls is created by buying one call at a lower strike price, selling two calls with a higher strike price and buying one call with an even higher strike price. All calls have the same expiration date, and the strike prices are equidistant. (a) Graph the profit curve for a butterfly spread created from European call options with strike prices 95, 100 and 105. When is a butterfly spread profitable? Describe what type of hedging protection it provides (b) Consider a butterfly spread created with European call options with strike prices ki, K. and K3, where KSK K3 and respective prices C. C. and Cy. Prove that: C1+C3 2 C