Choose the correct sets which represent the oxides as acidic, basic, neutral, amphoteric respectively. 

(i) $$\mathrm{CO_2}$$, $$\mathrm{MgO}$$, $$\mathrm{N_2O}$$, $$\mathrm{H_2O}$$ 

(ii) $$\mathrm{SO_2}$$, $$\mathrm{NO}$$, $$\mathrm{CO}$$, $$\mathrm{Al_2O_3}$$ 

(iii) $$\mathrm{P_2O_5}$$, $$\mathrm{ZnO}$$, $$\mathrm{NO}$$, $$\mathrm{Al_2O_3}$$ 

(iv) $$\mathrm{SO_3}$$, $$\mathrm{CaO}$$, $$\mathrm{N_2O}$$, $$\mathrm{PbO}$$