Which option describes a rule for using ARIA roles effectively?

The effective use of ARIA roles is best described by the principle that roles should be used only when semantic HTML alone is not sufficient. Semantic HTML provides inherent meaning and structure that help assistive technologies interpret the content correctly. By relying on semantic HTML first, accessibility is enhanced because it aligns with best practices for web development.

When semantic elements like headings, lists, and links are used appropriately, they already convey their roles and relationships within the content. However, there are cases where these elements do not suffice, particularly in complex web applications or custom components that do not conform to standard HTML elements. In such instances, ARIA roles can be introduced to provide meaning that was otherwise lacking. This targeted application ensures that ARIA roles enhance accessibility rather than create redundancy or confusion.

Using too many roles, or applying them indiscriminately to every HTML element, may lead to a cluttered and confusing experience for users of assistive technologies. Moreover, avoiding ARIA roles entirely would limit the capacity to communicate important roles and states for custom functionality, particularly in dynamic content. Therefore, the essential guideline is to complement semantic HTML with ARIA roles strategically and judiciously, ensuring the best possible outcomes for web accessibility.