The correct option is A 2,5,16
To balance the atoms other than H and O, coefficient 2 is added in front of CO2.
C is oxidized. Its oxidation number increases from +3 to +4. The net increase in the oxidation number is +2.
Mn is reduced. The oxidation number decreases from +7 to +2. The net decrease in the oxidation number is +5.
Hence, coefficient of C is multiplied with 5 and the coefficient of Mn is multiplied with 2.
To balance oxygen atoms, 7 water molecules are added to right. To balance H atoms, 15 protons are added to left.
Hence, the balanced reaction is 2MnO−4+5C2O2−4+16H+→10CO2+8H2O+2Mn2+.