I am confused on how to balance net ionic equations. I'm wondering if it's similar to redox equations or if there's a different process to it?

**Problem:**

Balance the net ionic equation

MnO_{4}^{-} + I^{-} -> I_{2} + MnO_{2}

(basic solution). What is the sum of the coefficients?

Choices:

a)21

b)23

c)29

d)27

e)25

Not sure I started out right for the problem...

Mn^{4+} + O_{4}^{-} + I^{-} -> I^{2-} + Mn^{4+} + O_{2}^{2-}

O_{4}^{-} + I^{-} -> I^{2-} + O_{2}^{2-}