Choose the correct equation for the standard enthalpy of formation of CO(g), where δH° for CO = -110.5 kJ/mol (gr indicates graphite):

a) (Δ H_f° = -110.5 , kJ/mol)
b) (Δ H_f° = -110.5 , kJ/mol , (gr))
c) (Δ H_f° = 110.5 , kJ/mol)
d) (Δ H_f° = 110.5 , kJ/mol , (gr))