Final answer:
WCF supports data exchange, message exchange, and service hosting, meaning that it facilitates all the listed functions for building distributed applications. Therefore, the answer is 'All of the above'.
Step-by-step explanation:
WCF, or Windows Communication Foundation, is a Microsoft framework for building service-oriented applications. WCF supports various functions essential for creating distributed and interconnected systems.
Among the capabilities it provides, WCF indeed supports data exchange, enabling different applications to communicate using common data formats; message exchange, facilitating the asynchronous passing of information between services; and service hosting, allowing services to be hosted in various environments including web servers, windows services, or even within applications themselves. Thus, the correct answer to what functions WCF supports is 4) All of the above.