If the demand for one commodity excludes another, it is said to be

The correct term for a situation where the demand for one commodity excludes another is "competitive demand." Competitive demand occurs when two or more products are in direct competition with each other because they serve a similar purpose or satisfy the same need. For example, if you have a craving for either a chocolate bar or a bag of potato chips, and you can only choose one, then the demand for one product competes with the demand for the other. In other words, when the price of one product increases or decreases, it affects the demand for the other product as consumers will make a choice between them. As a result, the products become substitutes for each other. Therefore, competitive demand refers to products that are competing for the same set of customers, and an increase in demand for one will decrease demand for the other.