已知在25℃、101kPa下，1gC₈H₁₈(辛烷)燃烧生成二氧化碳和液态水时放出48.40kJ 热量。表示上述反应的热化学方程式正确的是

A．C8H18(l)+25/2O2(g)=8CO2(g) +9H2O(g)△H=" -" 48.40kJ·mol -1

B．C8H18(l)+25/2O2(g)=8CO2 (g) +9H2O(l)△H=" -" 5518kJ·mol -1

C．C8H18(l)+25/2O2(g)=8CO2(g) + 9H2O(l) △H=" +" 5518kJ·mol -1

D．C8H18(l)+25/2O2(g)=8CO2 (g)+ 9H2O(l)△H= - 48.40kJ·mol -1