题目内容：

已知CH4(g)+H2O(g)=CO(g)+3H2(g) △H= +206kJ / mol

CH4(g)+CO2(g)=2CO(g)+2H2(g) △H= +247kJ / mol

C—H键的键能约为413 kJ / mol, O—H键的键能约为463 kJ / mol，H—H键的键能约为436 kJ / mol，则CO2中C=O键的键能约为

A.797.5 kJ / mol B.900.5 kJ / mol

C.962.5 kJ / mol D.1595 kJ / mol