已知：2Zn(s)+O₂(g)==2ZnO(s) △H=-701.0 kJ·mol^-1

2Hg(l)+O₂(g)==2HgO(s) △H=-181.6 kJ·mol^-1

则反应Zn(s)+ HgO(s)==ZnO(s)+ Hg(l)的△H为 [ ]

A．-259.7 kJ·mol^-1

B．-519.4kJ·mol^-1

C．+259.7 kJ·mol^-1

D．+519.4kJ·mol^-1