Which has square planar geometry

Allthe following complexes show a decrease in their weights when placed in a magnetic balance. Then which of the these has square planar geometry ?

Allthe following complexes show a decrease in their weights when placed in a magnetic balance. Then which of the these has square planar geometry ?

Which of the following species has square planar geometry ?

Which one of the following has a square planar geometry ?

Which of the following has a square planar geometry ?

Which one of the following has a square planar geometry ? [At. no. Co=27, Ni=28, Fe=26, Pt=78]

Which of the following has square planar geometry