Answer is: E- None of these.
NiCl₂ is nickel(II) chloride. Nickel chloride is salt.
KMnO₄ is potassium permanganate. Potassium permanganate is salt.
ZnSO₃ is zinc(II) sulphite. Zinc sulphite is salt.
SO₂ is sulfur(IV) oxide. Sulpfur oxide is oxide. Oxidation number of sulfur is +4 and oxygen has oxidation number -2.