Select the correct statement$(s)$ regarding the $[Ni(DMG)_2]$ complex compound.

$A$ mixture $X$ of $0.02 \, mol$ of $[Co(NH_3)_5SO_4]Br$ and $0.02 \, mol$ of $[Co(NH_3)_5Br]SO_4$ was prepared in $2 \, L$ of solution:
$1 \, L$ of mixture $X +$ excess of $AgNO_3 \to Y$
$1 \, L$ of mixture $X +$ excess of $BaCl_2 \to Z$
Number of moles of $Y$ and $Z$ respectively are

The complexes given below show:

Which statement is wrong?

The correct statements from the following are:
$A$. The strength of anionic ligands can be explained by crystal field theory.
$B$. Valence bond theory does not give a quantitative interpretation of kinetic stability of coordination compounds.
$C$. The hybridization involved in the formation of $\left[Ni(CN)_4\right]^{2-}$ complex is $dsp^2$.
$D$. The number of possible isomer$(s)$ of $cis-\left[PtCl_2(en)_2\right]^{2+}$ is one.
Choose the correct answer from the options given below:

The complex ion $[Co(en)_2Br_2]^+$ has two optical isomers. Their correct configurations are: