Which oxides form acidic solutions when added to water?

A.     ${{\text{P}}_{\text{4}}}{{\text{O}}_{{\text{10}}}}{\text{(s)}}$ and ${\text{S}}{{\text{O}}_{\text{3}}}{\text{(g)}}$ 

B.     ${\text{N}}{{\text{a}}_{\text{2}}}{\text{O(s)}}$ and ${\text{MgO(s)}}$

C.     ${\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}{\text{(s)}}$ and ${\text{Si}}{{\text{O}}_{\text{2}}}{\text{(s)}}$

D.     ${\text{MgO(s)}}$ and ${\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}{\text{(s)}}$

A