The correct option is Iron mixed with nickel and chromium.
Explanation
Stainless steel is an alloy designed specifically to resist corrosion and rusting, which are common issues with pure iron.
- Composition: The standard composition of stainless steel involves mixing Iron with Chromium and Nickel. Carbon is also present in small quantities to provide hardness.
- Role of Chromium: Chromium is the critical element responsible for rust resistance. When present (typically above 10.5%), it reacts with oxygen to form a thin, stable, and invisible layer of chromium oxide on the surface. This "passive layer" seals the iron from the environment and prevents further oxidation.
- Role of Nickel: Nickel is added to enhance the alloy's corrosion resistance, particularly in acidic environments, and to improve ductility and strength.
Comparison with other options:
- Copper and Zinc: This combination forms Brass, not stainless steel.
- Tin and Lead: This combination forms Solder, used primarily for joining electrical wires.
Key Takeaway: The defining characteristic of stainless steel is the addition of Chromium to Iron, which creates a self-healing oxide layer that prevents rust.