Andres wrote the following letter to the editor about the minimum wage the government requires employers to pay:

"I am a college student who has worked at a local restaurant for almost 1 1/2 years. I am always on time, I get along with my superiors and fellow employees, and yet I only make a little more than $4 an hour. There must be a change in the minimum-wage law; $4.25 per hour is too low to pay anybody."

Respond to the following question
Why is the restaurant's demand for the student's labor a derived demand?