Consider the metal complexes [ Ni ( en )_3]^2+( A ),[ NiCl_4]^2-( B ) and [ Ni ( NH_3)_6]^2+( C ). Choose the CORRECT option by considering the…

Consider the metal complexes $\displaystyle \left[\mathrm{Ni}(\mathrm{en})_3\right]^{2+}(\mathrm{A}),\left[\mathrm{NiCl}_4\right]^{2-}(\mathrm{B})$ and $\displaystyle \left[\mathrm{Ni}\left(\mathrm{NH}_3\right)_6\right]^{2+}(\mathrm{C})$. Choose the CORRECT option by considering the number of unpaired electrons present in (A), (B) and (C) respectively and the order of frequency of absorption.