What is an alloy? A. A substitution of one metal for another metal B. A metal with a changed oxidation state C. A combination of metal with another element D. A layering of one metal over another metal

The correct answer is the combination of a metal with another element.

We can confirm this because stainless steel is made of an iron and chromium alloy (iron is a metal; chromium is also a metal). Therefore, we can confirm that option C is the best choice.