Four successive members of the first row transition elements are listed below with atomic numbers. Which one of them is expected to have the highest $E_{{\text{M}}^{3+}/{\text{M}}^{2+}}^0$ value?

The standard reduction potentials ($E_{{\text{M}}^{3+}/{\text{M}}^{2+}}^0$) for the given elements are:$E_{{\text{Cr}}^{3+}/{\text{Cr}}^{2+}}^0=-0.41\text{V}$$E_{{\text{Mn}}^{3+}/{\text{Mn}}^{2+}}^0=+1.57\text{V}$$E_{{\text{Fe}}^{3+}/{\text{Fe}}^{2+}}^0=+0.77\text{V}$$E_{{\text{Co}}^{3+}/{\text{Co}}^{2+}}^0=+1.97\text{V}$${\text{Co}}^{3+}$ has the highest reduction potential because ${\text{Co}}^{2+}$ is relatively stable, and the $d^6$ to $d^7$ transition is energetically favorable under certain conditions.