Explanation

A. $[ \mathrm{NiCl}_4 ]^{2-}$

Nickel Oxidation State: $ \text{Ni}^{2+} $

Electron Configuration: $ 3d^8 $

Hybridization: $ sp^3 $

Unpaired Electrons: 2

Magnetic Property: Paramagnetic

B. $\mathrm{Ni}(\mathrm{CO})_4$

Nickel Oxidation State: $\text{Ni}$ (neutral)

Electron Configuration: $ 3d^8 4s^2 $

Hybridization: $ sp^3 $

Unpaired Electrons: 0

Magnetic Property: Diamagnetic

C. $[ \mathrm{Ni}(\mathrm{CN})_4 ]^{2-}$

Nickel Oxidation State: $ \text{Ni}^{2+} $

Electron Configuration: $ 3d^8 $

Hybridization: $ dsp^2 $

Unpaired Electrons: 0

Magnetic Property: Diamagnetic

D. $[ \mathrm{Ni}(\mathrm{H}_2\mathrm{O})_6 ]^{2+}$

Nickel Oxidation State: $ \text{Ni}^{2+} $

Electron Configuration: $ 3d^8 $

Hybridization: $ sp^3d^2 $

Unpaired Electrons: 2

Magnetic Property: Paramagnetic

E. $\mathrm{Ni}(\mathrm{PPh}_3)_4$

Nickel Oxidation State: $\text{Ni}$ (neutral)

Electron Configuration: $ 3d^8 4s^2 $

Hybridization: $ sp^3 $

Unpaired Electrons: 0

Magnetic Property: Diamagnetic

Overall, complexes A and D are paramagnetic as they have unpaired electrons.