For which of the following complexes will the value of $\Delta_0$ be the lowest?

Crystal field splitting energy $(CFSE)$ for $[CoCl_6]^{4-}$ is $18000 \ cm^{-1}$. The crystal field splitting energy $(CFSE)$ for $[CoCl_4]^{2-}$ will be (in $cm^{-1}$)

The correct statements among $I$ to $III$ are:
$I$. Valence bond theory cannot explain the color exhibited by transition metal complexes.
$II$. Valence bond theory can predict quantitatively the magnetic properties of transition metal complexes.
$III$. Valence bond theory cannot distinguish ligands as weak and strong field ones.

The correct order of energy of absorption for the following metal complexes is
$A: [Ni(en)_3]^{2+}, B: [Ni(NH_3)_6]^{2+}, C: [Ni(H_2O)_6]^{2+}$

In which one of the following complexes does the metal ion have a $t_{2g}^3 e_g^2$ configuration?

Given below are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $[CoCl(NH_3)_5]^{2+}$ absorbs at a lower wavelength of light with respect to $[Co(NH_3)_5(H_2O)]^{3+}$.
Reason $R$: It is because the wavelength of the light absorbed depends on the oxidation state of the metal ion.
In the light of the above statements,choose the correct answer from the options given below: