When iron reacts with oxygen in the moisture, rust builds up.
Rust does not appear immediately, it occurs gradually over time. Oxygen atoms form bonds with iron atoms that lead to the formation of iron oxides. The bond between metal atoms is weakened as a result. Corrosion is a redox reaction. Iron undergoes oxidation, there is an increase in oxidation number, and electrons are lost. Oxygen is an excellent oxidizing agent and iron is a reducing agent, so iron easily donates electrons to the oxygen.
The oxidation potential of Zn is more than Iron. Tin, copper, and nickel have a lower oxidation potential than iron. The most commonly used method to prevent metal from corrosion is galvanization. In galvanization, a protective zinc layer is applied to the metal.
As zinc has a greater tendency to oxidation than iron, it provides metal protection also known as cathodic protection. zinc rust instead of metal.
Hence, the correct option is B.