A.
Begin numbering at the end closest to the first branch, not the farthest.
Balanced chemical reaction: 2KClO₃ → 2KCl + 3O₂.
Potassium is metal from first group of Periodic table of elements, it has always oxidation number in compound +1.
Chlorine in the reactant state has oxidation number +5 (+1 + x + 3 · (-2) = 0) and it is reduced to -1 (+1 + x = 0) in the product state.
Oxygen in the reactant state has oxidation number -2 (+1 + 5 + 3 · x = 0) and it is oxidized to 0 (in molecule of oxygen) in the product state.
The single combination of pressure and temperature at which liquid water, solid ice, and water vapor can coexist in a stable equilibrium occurs at approximately 273.1575 K (0.0075 °C; 32.0135 °F) and a partial vapor pressure of 611.657 pascals (6.11657 mbar; 0.00603659 atm).[4][5] At that point, it is possible to change all of the substance to ice, water, or vapor by making arbitrarily small changes in pressure and temperature. And the temperature is called Triple point
21/4 * 4 * 2/3
21 * 2/3
42/3 = 14
