The correct answer is A. Zinc.
Galvanization is a process in which a thin layer of zinc is applied to iron or steel to protect it from rusting. The zinc forms a barrier between the iron and oxygen, preventing the iron from corroding.
Zinc is a good choice for galvanizing iron because it is a relatively inexpensive metal that is also highly resistant to corrosion. It is also easy to apply, and the zinc coating can be applied to a variety of iron and steel products.
Chromium is another metal that is sometimes used to galvanize iron. However, chromium is more expensive than zinc, and it is not as effective at preventing corrosion. Lead and antimony are not typically used to galvanize iron, as they are not as resistant to corrosion as zinc or chromium.
In conclusion, the metal used to galvanize iron to protect it from rusting is zinc. Zinc is a good choice for galvanizing iron because it is a relatively inexpensive metal that is also highly resistant to corrosion. It is also easy to apply, and the zinc coating can be applied to a variety of iron and steel products.