Chemistry Help???? Redox Reaction???

Question

1. Consider the following skeletal redox reaction:

   Sn²⁺ + NO₂^- --> Sn⁴⁺ + N₂

   Which of the following represents the correctly balanced tin half reaction?

   		Sn4+ + 2 e- --> Sn2+
   		Sn4+ --> Sn2+ + 2e-
   		Sn2+ + 2e- --> Sn4+
   		Sn2+ --> Sn4+ + 2e-