For which one of the following equations is $\Delta H^{\circ}_{react}$ equal to $\Delta H^o_f$ for the product :

Question

( A ) $CH_4(g) + 2Cl_2(g) \to CH_2Cl_2(l) + 2HCl(g)$
( B ) $Xe(g) + 2F_2(g) → XeF_4(g)$
( C ) $N_2(g) + O_3(g) \to N_2O_3(g)$
( D ) $2CO(g) + O_2(g) → 2CO_2(g)$