Final answer:
A futures contract typically specifies variables like contract size, delivery date, and specified grade, but not a contract premium, which is more commonly associated with options contracts.
Step-by-step explanation:
The variable typically not specified on a futures contract is: b) Contract premium. Futures contracts are standardized agreements that typically specify the contract size, delivery date, and specified grade of the commodity or financial instrument in question. The contract size denotes the quantity of the asset that is to be delivered, the delivery date specifies when the asset must be delivered, and the specified grade details the quality or grade of the commodity.
In contrast, a contract premium is not a term generally used in relation to futures contracts. Instead, premiums are more commonly associated with options contracts, where the premium is the price paid by the buyer to the seller for the right, but not the obligation, to buy or sell an asset at a predetermined price within a specified timeframe.