In an octahedral structure,which pair of $d$-orbitals is involved in ${d^2}sp^3$ hybridization?

Consider the transition metal ions $Mn^{3+}$, $Cr^{3+}$, $Fe^{3+}$, and $Co^{3+}$. All form low spin octahedral complexes. The correct decreasing order of unpaired electrons in their respective $d$-orbitals of the complexes is:

Which of the following pairs of structure and magnetic properties is correct for the tetracyanonickelate$(II)$ ion?

Which of the following complexes exhibits $sp^{3}d$ hybridization?

The hexafluoroferrate $(II)$ ion is an outer orbital complex. The number of unpaired electrons in it is .............

The hybridisation of $Ni$ centre in $[Ni(PPh_3)_2Cl_2]$ and $[NiCl_4]^{2-}$,respectively are