What spread positions would you form in the following cases:

a. In July, you expect the spot price of wheat to increase, and September and October wheat futures contracts are available.

b. The estimated relationship between the price of copper \(\left(P_{c}\right)\) and the price of lead \(\left(P_{L}\right)\) is \(\% \Delta P_{c}=0.9\left(\% \Delta P_{L}\right)\). You expect a decrease in the price of metals and futures contracts are available on both metals.