[LHM]

In the galvanizing process, iron is coated with zinc. The resulting chemical protection is most similar to that provided when:

A) a magnesium bar is connected to an iron pipe.
B) an iron can is plated with tin.
C) copper pipes are connected using lead solder.
D) a copper pipe is covered with epoxy paint.

I know that when you coat iron with zinc, the zinc is oxidized instead, but then this forms a protective layer over the zinc so that it isn't oxidized further. So I figured that perhaps the epoxy paint also acts like a protective layer and prevents the copper pipe from oxidizing, but the answer's A. I mean, I guess I can see why A could be the answer since the magnesium is oxidized instead of the iron, but how does this make it a better answer than the others, since the magnesium never really forms a protective layer like iron?

Thank you!

[Borek]

It asks about "most similar", not identical. ZnO layer is as resistant as a paint is, most of the protection comes from electrochemistry.