Which aspect is critical for ensuring a website is accessible to users with disabilities?

Clear and well-structured headers are fundamental for ensuring a website's accessibility because they provide a logical organization to the content, making it easier for users, especially those using screen readers, to navigate the information presented. Headers help delineate sections and subsections, allowing users to quickly understand the hierarchy of information and jump to the sections that are most relevant to them.

This structured approach benefits not only individuals with disabilities but also enhances the usability of a website for all users, as it promotes a cleaner, more organized presentation of content. When headers are implemented properly, they contribute significantly to the overall user experience by facilitating easier browsing and comprehension.

In contrast, the other options do not directly address the accessibility requirements as effectively. For instance, the use of bright colors may not consider color contrast, which is essential for users with visual impairments. Minimizing text information might lead to a lack of essential context or clarity, and avoiding multimedia altogether can diminish the interactivity and richness of the content offered on the website. Overall, well-structured headers remain a key component of accessible web design.