Coordination Compounds

The correct increasing order of stability of the complexes based on $\Delta_0$ value is :

1. I. $[\text{Mn}(\text{CN})_6]^{3-}$



2. II. $[\text{Co}(\text{CN})_6]^{4-}$



3. III. $[\text{Fe}(\text{CN})_6]^{4-}$



4. IV. $[\text{Fe}(\text{CN})_6]^{3-}$