Derived demand is normally used with reference to

Derived demand refers to the demand for a good or service that arises from the demand for another good or service. In other words, when the demand for one good or service is dependent on the demand for another good or service, the demand for the former is said to be derived. The most common application of derived demand is with regards to factors of production, such as labor or capital. For example, the demand for labor is derived from the demand for the goods or services that the labor is used to produce. Similarly, the demand for capital is derived from the demand for the goods or services that the capital is used to produce. Therefore, the correct answer is "the factors of production".