Concept:The demand for a factor input that comes from the demand for the product it helps to produce is called derived demand.
Explanation:Factor inputs are not demanded for themselves.
They are demanded because they are needed to produce final goods and services.
So, the demand for a factor input depends directly on the demand for its output.
For example, labour is demanded because goods and services are demanded.
When the demand for goods and services rises, producers demand more labour.
Likewise, if the demand for the final output falls, the demand for the factor input also falls.
Therefore, the demand for a factor input is derived from the demand for the product it produces.
Answer:D. derived demand