For Co(II), (choose incorrect statement) :

 

Dmg does not contains two donor atoms which can coordinate to the central metal atom or ion it does not form planar complexes with bidentate monoanionic ligand.

Since Ethylenediamine is a chelating ligand. planar complexes are not formed with a neutral bidentate ligand like ethylenediamine.

Tetrahedral complexes are generally formed by terminal ligand and a bridging ligand.