Calculate ΔHrxn for the following reaction: Fe₂O₃(s) + 3CO(g) → 2Fe(s) + 3CO₂(g). Use the following reactions and given ΔH values: 2Fe(s) + 3/2O₂(g) → Fe₂O₃(s), ΔH; CO(g) + 1/2O₂(g) → CO₂(g), ΔH.
a) -691.3 kJ
b) -641.3 kJ
c) -611.4 kJ
d) -721.2 kJ