Which of the following data formats does SOAP (Simple Object Access Protocol) support?

SOAP (Simple Object Access Protocol) primarily supports XML (eXtensible Markup Language) as its data format. SOAP is designed for exchanging structured information in the implementation of web services, and XML serves as a universally recognized format that allows for a variety of data types and structures.

The use of XML in SOAP provides a consistent and standardized way to encode messages that can be easily understood and processed by different systems, regardless of the underlying programming language or platform. XML's ability to define custom markup makes it a flexible choice for representing complex data types and relationships between different pieces of information in SOAP messages.

While JSON, YAML, and HTML are important data formats in their own right, they are not used in the context of SOAP. JSON is often employed in RESTful services due to its lightweight nature and ease of use with JavaScript, while YAML is typically utilized for configuration files, and HTML is focused on rendering web pages rather than data exchange in the context of web services. Thus, the clear alignment of SOAP with XML confirms that it is the correct answer.