2.12. Show that, if the futures price of a commodity is greater than the spot price during the delivery period, then there is an arbitrage opportunity. Does an arbitrage opportunity exist if the futures price is less than the spot price? Explain your answer.

2.14. Explain what a stop-limit order to sell at 20.30 with a limit of 20.10 means.

2.28. A company enters into a short futures contract to sell 5,000 bushels of wheat for 450 cents per bushel.The initial margin is $3,000 and the maintenance margin is $2,000.What price change would lead to a margin call? Under what circumstances could $1,500 be withdrawn from the margin account?