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.
