The correct set of oxides arranged in the proper order of basic, amphoteric, acidic are $BaO , Al _2 O _3, SO _2$
Oxides of non-metallic elements are acidic such as $CO _2, NO _2, SO _2$ etc. Oxides of less electropositive elements (such as $BeO , Al _2 O _3, Bi _2 O _3, ZnO$ etc. ) are amphoteric i.e. these behaves as acids toward strong bases and as bases towards strong acids. Oxides of electropositive elements $\left( Na _2 O , CaO , Tl l_2 O , BaO\right.$ etc.) are basic and contain discrete $O ^{2-}$ ions.