Stainless steel is an alloy comprising of

Analyze the question: We need to identify which elements make up stainless steel from the options given.

Concept: An alloy is a mixture of a metal with other elements, made to improve properties like strength and resistance to corrosion.

• Steel is iron (Fe) with a small amount of carbon (C).
• Stainless steel is steel with added chromium (Cr), and often nickel (Ni), to resist rusting.

In real life, stainless steel is Fe + C + Cr (at least about 10.5% chromium), usually with Ni as well.

Checking the options:

• A. Fe and C: This is ordinary carbon steel, with no rust-resisting additive. Not stainless steel.
• B. Fe and Ni: This leaves out carbon. Fe–Ni alloys exist (e.g., Invar), but this is not stainless steel.
• C. Fe, C and Ni: This contains iron, carbon, and nickel. Chromium is missing, but of the choices given, this is the closest to stainless steel because it includes steel (Fe + C) plus nickel, a key alloying element.
• D. Fe, C and Al: Aluminium is not a characteristic component of stainless steel.

Note: Strictly speaking, chromium is the essential element in stainless steel, and none of the options lists it. The question is a bit incomplete, but C is the most acceptable answer.

Answer: C

Exam tip: Remember "stainless = steel + chromium (and nickel)". If Cr isn't among the options, choose the one that has Fe, C, and Ni. Also remember: Steel = Fe + C; Brass = Cu + Zn; Bronze = Cu + Sn.