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 $E^0_{M^{3+} /m^{2+}}$ value ?

Question

$\begin{array}{1 1} (1) Cr(Z=24) \\ (2) Mn(Z=25) \\ (3) Fe(Z=26) \\(4)Co(Z=27) \end {array}$