Which of the following can show geometrical isomerism? Assume square planar geometry for the Pt(II) complex and octahedral geometry for the Co(III) complexes.

1. A$[\mathrm{Co}(\mathrm{NH}{}_3){}_5\mathrm{Cl}]{}^{2+}$
2. B$[\mathrm{Pt}(\mathrm{NH}{}_3){}_2\mathrm{Cl}{}_2]$
3. C$[\mathrm{NiCl}{}_2\mathrm{Br}{}_2]{}^{2-}$ (tetrahedral)
4. D$[\mathrm{Co}(\mathrm{NH}{}_3){}_4\mathrm{Cl}{}_2]{}^{+}$