The pair(s) of complexes wherein both exhibit tetrahedral geometry is(are) (Note: py = pyridine Given:…

${\left[{\mathrm{FeCl}}_4\right]}^{-}$: ${\mathrm{sp}}^3$ Tetrahedral

${\left[\mathrm{Fe}{\left(\mathrm{CO}\right)}_4\right]}^{2-}$ : ${\mathrm{sp}}^3$ Tetrahedral (Isoelectronic to $\mathrm{Ni}{\left(\mathrm{CO}\right)}_4$)

${\left[\mathrm{Co}{\left(\mathrm{CO}\right)}_4\right]}^{-}$ : ${\mathrm{sp}}^3$ Tetrahedral (Isoelectronic to $\mathrm{Ni}{\left(\mathrm{CO}\right)}_4$)

${\left[{\mathrm{CoCl}}_4\right]}^{2-}$ : ${\mathrm{sp}}^3$ Tetrahedral

$\left[\mathrm{Ni}{\left(\mathrm{Co}\right)}_4\right]$ : ${\mathrm{sp}}^3$ Tetrahedral (Complex of Mond's process)

${\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]}^{2-}$ : ${\mathrm{dsp}}^2$ square planar (Cyanide is strong field ligand)

${\left[\mathrm{Cu}{\left(\mathrm{Py}\right)}_4\right]}^{+}$ : ${\mathrm{sp}}^3$ Tetrahedral

${\left[\mathrm{Cu}{\left(\mathrm{CN}\right)}_4\right]}^{3-}$ : ${\mathrm{sp}}^3$ Tetrahedral