Consider the following investments
* An investor short sells a stock at a price S, and writes an al-the-money call option on the same stock with a strike price of k
* An investor buys one put with a strike price of K1 and one call option at a strike price of K2 with K1 ≤ K2.
(a) Plot the expiration payoff diagrams in each case
(b) How would these diagrams look some time before expiration?