Suppose that c,, c2, and c3 are the prices of European call options with strike prices Kx, K2, and K3, respectively, where A"3 > K2 > Kx and A"3 — K2 = K2 — Kx. All options have the same maturity. Show that c2«:0.5(C l+c3 )

(Hint: Consider a portfolio that is long one option with strike price Kx, long one option with strike price A"3, and short two options with strike price K2.)