单项选择题

A.C(石墨)+O2(g)=CO2(g)△H=-394kJ/mol
B.2C(石墨)+2O2(g)=2CO2(g)△H=-394kJ/mol
C.C+O2=CO2△H=394kJ/mol
D.C(石墨)+O2(g)=CO2(g)△H=394kJ/mol