A-I, B-II, C-III, D-IV

A-II, B-III, C-IV, D-I

A-III, B-IV, C-I, D-II

A-IV, B-I, C-II, D-III

A = B < D < C

C = D < B < A

C < B < D < A

A = B < C < D

$\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ and $\left[\mathrm{NiCl}_4\right]^{2-}$ are diamagnetic and $\mathrm{Ni}(\mathrm{CO})_4$ is paramagnetic.

$\mathrm{Ni}(\mathrm{CO})_4$ is diamagnetic and $\left[\mathrm{NiCl}_4\right]^{2-}$ and $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ are paramagnetic.

$\mathrm{Ni}(\mathrm{CO})_4$ and $\left[\mathrm{NiCl}_4\right]^{2-}$ are diamagnetic and $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ is paramagnetic.

$\mathrm{Ni}(\mathrm{CO})_4$ and $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ are diamagnetic and $\left[\mathrm{NiCl}_4\right]^{2-}$ is paramagnetic.

III $<$ IV $<$ I $<$ II $<$ V

III $<$ I $<$ IV $<$ V $<$ II

III $<$ I $<$ IV $<$ II $<$ V

III $<$ I $<$ II $<$ IV $<$ V