Which standard is widely used as a guideline for web accessibility?

The Web Content Accessibility Guidelines (WCAG) are the definitive standards used for web accessibility. These guidelines were developed by the World Wide Web Consortium (W3C) to ensure that online content is accessible to a wide range of users, including those with disabilities. WCAG provides a comprehensive framework that encompasses various principles, guidelines, and success criteria aimed at making web content more perceivable, operable, understandable, and robust for everyone.

WCAG emphasizes key concepts such as text alternatives for non-text content, keyboard accessibility, sufficient contrast, and the use of clear language. Adhering to these guidelines helps organizations create websites that are inclusive and compliant with accessibility laws and regulations, thereby enhancing the user experience for people with disabilities.

The other options, while related to standards and regulations, do not specifically focus on web accessibility. For instance, ISO 9001 pertains to quality management systems, GDPR is focused on data protection and privacy, and W3C Best Practices offer general advice on web development but do not specifically address accessibility. Thus, the prominence and utility of WCAG in the realm of web accessibility make it the widely accepted guideline.