Which oxides are acidic?

I.     ${{\text{P}}_{\text{4}}}{{\text{O}}_{{\text{10}}}}$

II.     ${\text{S}}{{\text{O}}_{\text{3}}}$

III.     ${\text{N}}{{\text{a}}_{\text{2}}}{\text{O}}$

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

A