Which of the following is an example of a "hard commodity"?

A "hard commodity" typically refers to natural resources that are mined or extracted. These commodities are characterized by their tangible nature and are usually used in industrial applications. Copper serves as a prime example of a hard commodity because it is a metal that is mined from the earth and has significant use in various industries, including construction, electronics, and manufacturing, due to its excellent conductivity and malleability.

In contrast, the other options listed—corn, coffee, and barley—are categorized as "soft commodities." Soft commodities are usually agricultural products that are grown and harvested, which differentiates them from hard commodities that are extracted from the earth. Corn, coffee, and barley all represent agricultural goods that depend on farming and seasonal conditions for their production. This distinction between hard and soft commodities is crucial for understanding commodities trading and market dynamics.