The no of moles of $KMnO_4$ that will be needed to react with one mole of sulphite ion in acidic solution

Question

$(a)\;\large\frac{2}{5}$$\qquad(b)\;\large\frac{3}{5}$$\qquad(c)\;\large\frac{4}{5}\qquad$$(d)\;\large\frac{1}{2}$