A square planar complex is formed by the hybridization of which atomic orbitals?

Out of the following four complexes of $\mathrm{Ni}$, the complexes which will be attracted by magnetic field are:

(I) ${\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]}^{2-}$

(II) ${\left[{\mathrm{NiCl}}_4\right]}^{2-}$

(III) $\left[\mathrm{Ni}{\left(\mathrm{CO}\right)}_4\right]$

(IV) ${\left[\mathrm{Ni}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$