The correct option is A Both Fe atoms are in the same oxidation state
In the complex, K2Fe[Fe(CN)6]:
Let, the oxidation state of Fe be x
Therefore,
1×2+2x−1×6=0⇒2+2x−6=0⇒2x=4⇒x=+2
So, both Fe atoms are in same oxidation state (+2).
Coordination number of iron is 6.
In complex, hybridisation of central atom is d2sp3 as CN− is a strong field ligand. So, it is a low spin complex.