Which of the following chemical equations show oxidation-reduction reactions?

a) Mg(s) + I2(aq)---> MgI2(s)

b) Pb(ClO4)2(aq) + 2 KI(aq)---> PbI2(s) + KClo4(aq)

c) Fe2O3(s) + 3 CO(g)---> 2 Fe(s) + 3 CO2(g)

Check the change in oxidation number in each reaction and then you can select the reaction in which there is a change in oxidation number