Final answer:
The language used to describe the functionality of a SOAP server is the A)Web Service Description Language (WSDL).
Step-by-step explanation:
The XML-based interface definition language used to describe the functionality offered by a Simple Object Access Protocol (SOAP) server is Web Service Description Language (WSDL). It provides a model and an XML format for describing web services. WSDL allows for the abstraction and definition of the services and their respective messages, making it essential in defining how the service is called and what parameters it expects. While other options like Web Application Description Language (WADL) and Swagger are also used to describe web services, they are typically associated with Representational State Transfer (REST) services.
The XML-based interface definition language used to describe the functionality of a SOAP server is Web Service Description Language (WSDL).
A. Web Service Description Language (WSDL)