What best describes XML?

The description of XML as Extensible Markup Language is accurate because XML is designed specifically to facilitate the transportation and storage of data in a structured format that is both human-readable and machine-readable. It allows developers to create custom tags that define the data, making it flexible for a wide array of applications.

XML’s extensibility is one of its key strengths, enabling users to define their own tags and structure based on the requirements of the data’s context, rather than being limited to a predefined set of tags as seen in HTML. This characteristic makes XML highly suitable for data interchange between systems, allowing different applications to communicate effectively and share data regardless of their underlying platforms or technologies.

The other options describe different technologies or methods: HyperText Markup Language is specific to creating and structuring content on the web, Database Query Language relates to querying databases, and Simple Markup Language does not have a defined standard in the context of structured data representation. Therefore, defining XML as Extensible Markup Language captures its primary attributes and purpose accurately.