For the Combustion Reaction of Methane,ΔH°_f Is Zero for ________

Multiple Choice

For the combustion reaction of methane,ΔH°_f is zero for ________. CH₄ (g) + O₂ (g) → 2H₂O(g) + CO₂ (g)

A) O₂ (g)
B) CH₄ (g)
C) CO₂ (g)
D) H₂O (g)
E) Both O₂ (g) and CH₄ (g)