Shelby wants to buy pain-relief medication. At the store, she selects a brand called Motrin™ and a brand called Advil™. She is supposed to see that each medication’s packages list the drug ibuprofen as the active ingredient.

Why is “ibuprofen” listed on both packages?

It is a generic name.
It is a trade name.
It is a chemical name.
It is a diagnostic name.