How should the messages be delivered to the clients?

Your application produces messages by client applications. The number of clients interested in the
messages varies continuously at run time. Any client can process any message, but a message
must be processed exactly once.
How should the messages be delivered to the clients?

A.
Using a Java Message Service (JMS) topic

B.
Using a Java Message Service (JMS) queue

C.
Using XML over HTTP

D.
Using a Simple Object Access Protocol (SOAP) web service