[单选题]
For the combustion of magnesiu(/vb v(sitkf 4m, l(c+ t k8w2snhxi k:y0which of the following are correct for the products and enthalpy x+0 ic2hlnw k8k: yst(of reaction?
Mg(s)+$O_2$(g)→? ΔH?
A. $MgO$;ΔH>0
B. $MgO_2$;ΔH>0
C. $MgO$;ΔH<0
D. $MgO_2$;ΔH<0