# IUPAC name for [Fe(CN)_6]^(-4) is? (A) hexacynoferrate (II) (B) hexacyno iron (II) (C) hexacynoferrate (IV) (D) hexacynoferrate (II) ion

Well IUPAC would probably call this $\text{hexacyanoferrate(II)}$
So $\text{option D}$ is the one to order. I would simply call this $\text{ferrocyanide anion}$. This is clearly a salt of $F e \left(I I\right)$ inasmuch as each of the cyanide ligands bears a formula negative charge:
${\left[F e {\left(C \equiv N\right)}_{6}\right]}^{4 -} \equiv F {e}^{2 +} + 6 \times \text{^(-):C-=N, "i.e. ferrous ion}$. Do the charges balance?