Which markup language is designed to be both human-readable and machine-readable for encoding documents?

• A. HTML5
• B. JSON
• C. XML Extensible Markup Language
• D. YAML

Answer: (C)

This question tests a markup language designed for encoding documents in a way that both humans can read and machines can parse. XML fits this goal best because it uses descriptive tags to mark data and a hierarchical structure that clearly expresses the relationships inside a document. The tags convey meaning, and documents must be well-formed, with proper nesting and closing tags, which makes them easy for both people to understand and software to process. Moreover, XML is extensible: you can define your own tags to suit different vocabularies, and you can validate documents against schemas or DTDs to ensure they conform to a particular structure. This combination—descriptive, self-contained markup that is both readable and machine-processable—is why XML is the go-to example for encoding documents.

HTML5, while a markup language, is primarily geared toward presentation and rendering in web browsers rather than encoding documents for data interchange. JSON focuses on data interchange in a lightweight, human-readable format but is not a markup language. YAML emphasizes human-friendly data serialization and is not used as a markup language for encoding documents.