It is an experimental fact that :

$\mathrm{DMG}+\mathrm{Ni}\left(\mathrm{II}\right)\text{ salt }+{\mathrm{NH}}_4\mathrm{OH}⟶$ Red precipitate Which of the following is wrong about this red precipitate? 

Since there are two unpaired electrons indimethylglyoxime $\left[\mathrm{Ni}(\mathrm{DMG}{)}_2\cdot \right]\left(3d^8\right)$ it is paramagnetic in nature. $\mathrm{DMG}+\mathrm{Ni}\left(\mathrm{II}\right)\text{ salt }+{\mathrm{NH}}_4\mathrm{OH}⟶\left[\mathrm{Ni}(\mathrm{DMG}{)}_2\cdot \right]$ Red precipitate
Hence, option C is correct.