What is the main goal of Extensible Hypertext Markup Language (XHTML)?

The primary goal of Extensible Hypertext Markup Language (XHTML) is to provide a transition from HTML to XML. XHTML was developed to reformulate HTML as an XML application, which allows for a more structured and stricter syntax. This transition is significant because XML emphasizes the need for well-formed documents, which helps ensure that web pages are correctly interpreted by browsers and other user agents.

By aligning HTML with XML, XHTML allows for greater flexibility and interoperability across different web technologies. It makes use of XML's features, such as separating content from presentation and facilitating data exchange, which is particularly important as the web continues to evolve and require robust data handling capabilities. As a result, XHTML enables developers to create web content that is both human-readable and machine-readable, aiding in the push towards a more semantic web.

The other options, while related to web development, do not accurately capture the primary purpose of XHTML. Focusing on simplifying web design, maintaining standards, or enhancing multimedia support does not address the core objective of facilitating a smooth transition to a more structured and extensible markup language format.