If a Service Consumer Program Needs to Get Data from a Service

If a service consumer program needs to get data from a service that is not available, it can poll the service by periodically issuing a request message. This type of interaction can be inefficient because it can lead to unnecessary message transmissions. Which of the following statements describes a solution to this problem?

A) By applying the Messaging Metadata pattern, the service consumer can write a request identifier in the message header. Service agents then intercept the request messages and do not forward those that contain a previously detected identifier. This practice eliminates the delivery of the duplicate messages to the service.
B) The Event-Driven Messaging pattern can be applied to establish a messaging framework in which service consumers are automatically notified of relevant runtime service events.
C) By applying the Atomic Service Transaction pattern, a service can be designed to invoke an alternative exception handling process when it is unavailable to receive a given message.
D) None of these statements describe solutions that directly solve this problem.