下列热化学方程式表示可燃物的燃烧热的是（   ）

A．H2(g)+Cl2(g)=2HCl(g)△H=-184.6kJ·mol^-1

B．CH4(g)+2O2(g)=2H2O(g)+CO2(g)△H=-802.3kJ·mol^-1

C．CO(g)+1/2 O2(g)=CO2(g)△H=-283kJ·mol^-1

D．2H2(g)+O2(g)=2H2O(g)△H=-571.6kJ·mol^-1