What is the usual property of oxides of Group III and IV?

Correct answer: (a) Basic and Acidic (i.e., Amphoteric)

Explanation

Oxides of Group III and IV elements typically behave as amphoteric oxides, reacting with both acids and bases.

An acidic oxide forms an acid with water and a basic oxide forms a base; amphoteric oxides show both characters.

Down these groups the oxides shift from more acidic at the top to more basic at the bottom, but never lose acidic character fully, so they are neither purely neutral.