In ${\mathrm{Na}}_2\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_5\mathrm{NO}\right]$ Sodium nitroprusside:

Which of the following have square planar geometry-

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

(b)${\left[\mathrm{Cu}{\left({\mathrm{NH}}_3\right)}_4\right]}^{+2}$

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

(d) ${{\mathrm{ClF}}_4}^{-}$