Select correct statement regarding [Ni(DMG)₂] complex compound.

EAN=Z−X+Y
Z=Atomic number of the metal
X=Number of electrons lost during the formation of the metal ion from its atom
Y=Number of electrons donated by the ligands
EAN=Z−X+Y
EAN=28−2+8=34

To achieve EAN of 36, [Ni(DMG)₂​], needs two electrons.
 However there are few exceptions from EAN rule. hence, [Ni(DMG)_2​] does not act as oxidizing agent. Thus option 1 is incorrect.
This complex has extra stability due to the formation of metal chelate. Thus option 2 is incorrect.

The IUPAC name of the compound [Ni(DMG)₂​] is Bis(dimethylglyoximato)nickel(II).Thus option 3 is correct.

The ligand DMG is a bidentate ligand and not ambidentate ligand. Hence, it contains only one donor site which is oxygen atom. Thus option 4 is incorrect.