When oxigen o2 is pass though an electrical spark (lighting is a good natural source of electrical spark)

Which of the following represents the balanced reduction half-reaction from the redox reaction? (2 points) pb + pd(no3)2 yields pb(no3)2 + pd pb yields pd2+ + e- pd2+ + 2e- yields pd pb + e- yields pb 2 pd2+ + 4 e- yields 2 pd