The crystal field stabilization energy $(CFSE)$ of $[Fe(H_2O)_6]Cl_2$ and $K_2[NiCl_4]$,respectively,are

Consider the metal complexes $[Ni(en)_3]^{2+}$ $(A)$, $[NiCl_4]^{2-}$ $(B)$ and $[Ni(NH_3)_6]^{2+}$ $(C)$. Choose the $\text{CORRECT}$ option by considering the number of unpaired electrons present in $(A)$, $(B)$ and $(C)$ respectively and the order of frequency of absorption.

For an octahedral complex,which of the following $d-$electronic configuration will give the maximum magnitude of crystal field stabilization energy,in terms of $\Delta_{o}$?

Given below are two statements:
Statement $I$: Presence of a large number of unpaired electrons in transition metal atoms results in higher enthalpies of their atomisation.
Statement $II$: $d_{xy} = d_{xz} = d_{yz} < d_{x^2-y^2} = d_{z^2}$ and $d_{x^2-y^2} < d_{xy} = d_{xz} = d_{yz}$ are the $d$-orbital splittings in $[Fe(H_2O)_6]^{3+}$ and $[Ni(Cl)_4]^{2-}$ complex ions respectively.
In the light of the above statements,choose the correct answer from the options given below:

Crystal field stabilization energy for high spin $d^4$ octahedral complex is

The complex with the highest magnitude of crystal field splitting energy $\left(\Delta_0\right)$ is