Oxides of aluminium and zinc are :

According to the NCERT textbook, most metal oxides are basic in nature. However, some metal oxides, such as aluminium oxide ($Al_2O_3$) and zinc oxide ($ZnO$), show both acidic as well as basic behaviour. Such metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides. Therefore, option (c) is correct.

• Option (a) is incorrect because these oxides are not purely acidic; they also exhibit basic properties.
• Option (b) is incorrect because although most metal oxides are basic, aluminium and zinc oxides are exceptions that also exhibit acidic properties.
• Option (d) is incorrect because neutral oxides do not react with either acids or bases, whereas amphoteric oxides react with both.