Final answer:
XML (b) is the correct answer as it allows users to define their own tags and is used for structured data storage and transport on the web.
Step-by-step explanation:
The correct answer is b) XML. XML, which stands for Extensible Markup Language, is a markup language that allows users to define their own customized tags. It is a flexible text format used chiefly for storing and transporting structured data. Unlike HTML, which has predefined tags, XML does not come with a set of predefined markup tags, making it highly adaptable for various types of data representation and exchange on the web, such as configuration files, web services, and transporting data between different systems. With XML, developers can create tags that suite the needs of the content, ensuring both words and pictures are structured appropriately for easy processing and integration. It is essential for developers to define their own document structure, ensuring that the XML document is capable of being understood and correctly used by any application that processes it.