Which of the following best describes a futures contract?

A futures contract is best described as an agreement to buy or sell a specified quantity of an underlying asset at a predetermined price on a specific date in the future. This is a standardized financial agreement that is typically traded on exchanges. It allows parties to hedge against price fluctuations or to speculate on price movements of the underlying asset, which can be commodities, currencies, or financial instruments.

The correct description emphasizes that both the quantity and price are defined in advance, along with a specific settlement date. This is crucial for traders who rely on futures contracts for planning and risk management.

The other options inaccurately describe the characteristics of futures contracts. For instance, agreeing to buy or sell at "random future prices" does not capture the standardization and specificity inherent in futures contracts. Furthermore, the notion of a lifetime guarantee to invest in commodities does not align with the finite terms characteristic of futures. Lastly, the idea of a contract for purchasing shares in future technology is not applicable, as futures contracts pertain more broadly to various underlying assets rather than being limited to any singular sector like technology.