# What does “totally reduced” mean?

My textbook mentions that:

Iron is unable to be totally reduced... the most common non-zero oxidation states of iron is (o for oxidation, r for reduction) are: +2r, +3, +4o, +5o, +6o.

I thought it maybe meant going to $\ce{Fe^4+}$ (as the most reduced I commonly see is $\ce{Fe^3+}$), but then upon googling there is also $\ce{Fe^5+}$ ions, so how far does it have to go until it is totally reduced (if this is even what it meant by totally reduced)? Edit: Sorry, got reduction and oxidation mixed up (thanks for pointing this out DVSA). However, my question still stands, though replacing the above with more to e.g. $\ce{Fe^4-}$ than $\ce{Fe^3-}$ .

The question, for context, is below (I have already typed up what I think are the relevant parts above). FYI the answer is D, but I want to know what B means.

• Sounds fishy to me - iron can be reduced to $\ce{Fe^0}$, even though it is reactive is aqueous/oxygen-rich environments. From Wikipedia: "Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen and water. Fresh iron surfaces appear lustrous silvery-gray, but oxidize in normal air to give hydrated iron oxides, commonly known as rust. " – Todd Minehardt Nov 12 '16 at 20:47
• Thanks Todd. You were right it was a fishy statement and a misleading question from me. See comment on DSVA's answers. – K-Feldspar Nov 12 '16 at 21:46