题目内容：

已知1 mol CH4气体完全燃烧生成气态CO2和液态H2O，放出890.3 kJ热量，则表示该反应的热化学方程式正确的是

A. CH4(g)＋2O2(g)＝CO2(g)＋2H2O(g)　ΔH＝＋890.3 kJ·molˉ1

B. CH4(g)＋2O2(g)＝CO2(g)＋2H2O(l)　ΔH＝－890.3 kJ·molˉ1

C. CH4(g)＋2O2(g)＝CO2(g)＋2H2O(l)　ΔH＝＋890.3 kJ·molˉ1

D. CH4(g)＋2O2(g)＝CO2(g)＋2H2O(g)　ΔH＝－890.3 kJ·molˉ1