d
\((d)\) In complexes \([Rh(H_2O)_6]^{3+}\) and \([Co(H_2O)_6]^{3+}\) , central  metal cations have same oxidation state as well as same ligands and they fall in same group, but \(\Delta_0\) of \([Rh(H_2O)_6]^{3+} > \Delta_0\) of \([Co(H_2O)_6^{3+}]\) because \(Rh^{3+}\) has high \(Z_{eff}\) value than \(CO^{3+}\).