Which statement correctly describes the general nature of metal oxides and non-metal oxides?

Correct answer: Metal oxides are generally basic and non-metal oxides are generally acidic

The governing concept is the acid-base nature of oxides. Many metal oxides react with acids to form salt and water, so they are generally basic; for example, CuO reacts with hydrochloric acid. Many non-metal oxides react with water to form acids or with bases to form salts, so they are generally acidic; carbon dioxide is a common example. The word generally matters because exceptions such as amphoteric oxides exist. Thus option A is correct.