Identify balanced equations from the following

In a balanced chemical equation, A, B, D are balanced in both

reactants and products side

Ex:  ${\mathrm{H}}_2+{\mathrm{O}}_2\to {\mathrm{H}}_2{\mathrm{O}}_2 \& 2{\mathrm{H}}_2+{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}$ 

$2\mathrm{Mg}+{\mathrm{O}}_2\to 2\mathrm{MgO}$