下列各组热化学方程式中，△H前者大于后者的是
①C(s)＋O2(g)＝CO2(g)；    C(s)＋1/2O2(g)＝CO(g)
②S(s)＋O2(g)＝SO2(g)；    S(g)＋O2(g)＝SO2(g)
③H2(s)＋1/2O2(g)＝H2O(l)；    2H2(g)＋O2(g)＝2H2O(l)
④2KOH (aq) ＋H2SO4(aq)＝K2SO4(aq)＋2H2O (l)；
2KOH (aq) ＋H2SO4(浓)＝K2SO4(aq)＋2H2O (l)

A．①③

B．②④

C．①②③

D．②③④