The ratio of chromium to iron to carbon varies
among the different types of stainless steel.
therefore, stainless steel is classified as
(1) a compound (3) a mixture
(2) an element (4) a substance

mixture

Explanation:

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water

Element is a pure substance which is composed of atoms of similar elements. It can not be decomposed into simpler constituents using chemical reactions.Example: Copper

Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present.Example: Alloys

As steel is made up of combination of carbon and chromium and are not present in any fixed ratio , steel is classified as a mixture.

i believe it is c.) 1575 j.