Iron is made from a reaction of iron oxide with carbon monoxide in the following reaction: Fe₂O₃(s) + 3 CO(g) -> 2 Fe(s) + 3 CO₂(g) Using Hess' Law, calculate the enthalpy of reaction given:
a) -71 kJ/mol
b) -94 kJ/mol
c) -142 kJ/mol
d) -213 kJ/mol