Which protocol specification allows for the exchange of structured information in web services?

The correct response is Simple Object Access Protocol (SOAP) because SOAP is specifically designed for exchanging structured information in web services. It is a messaging protocol that uses XML to encode its messages, enabling the communication between client and server applications over a network. SOAP provides a way to implement web services in a platform-agnostic manner, ensuring that different systems can interact with each other through a standard set of rules for messaging, which includes aspects like security, transaction management, and encoding of data types.

This focus on structured data exchange makes SOAP particularly suited for environments where there is a need for strict data typing and contracts, such as in enterprise applications where formal service definitions are necessary. Other protocols listed do not serve this function. For example, HTTP is a foundational protocol used for transferring web pages but does not specifically facilitate the structured exchange of information. FTP is primarily used for transferring files between computers and does not define how web services should format or transmit messages. RTP is used for delivering audio and video over networks and does not pertain to web services.