The correct order of the following complexes in terms of their crystal field stabilization energies is :

Identify the homoleptic complex(es) that is/are low spin.

(A) $\left[\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NO}\right]^{2-}$

(B) $\left[\mathrm{CoF}_6\right]^{3-}$

(C) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$

(D) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$

(E) $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$

Choose the correct answer from the options given below :

From the magnetic behaviour of $\left[\mathrm{NiCl}_4\right]^{2-}$ (paramagnetic) and $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ (diamagnetic), choose the correct geometry and oxidation state.

In which of the following complexes the CFSE, $\Delta_o$ will be equal to zero?