Answer : 3. "Both A and B"
Explanation :

An amphoteric oxide is a type of oxide that can act as both an acid and a base. This means it can react with both acids and bases, either accepting or donating protons (H⁺ ions) depending on the pH of the solution. Amphoteric oxides exhibit this dual behavior because they have both acidic and basic properties. Aluminum oxide (Al₂O₃) and zinc oxide (ZnO) are examples of common amphoteric oxides.