When this equation is balanced using the smallest whole

Question

For the reaction between permanganate ion and sufite ion in basic solution, the unbalanced equation is:

MnO₄^- + SO₃^2-  MnO₂ + SO₄^2-

When this equation is balanced using the smallest whole number coefficients possible, the number of OH^- ions is(a) two on the right.(b) two on the left.(c) three on the right.(d) four on the right.(e) four on the left.