Question: In MBMS (Multimedia Broadcast/Multicast Service), what is the primary purpose of the 'Availability-Time' attribute in the context of file repair service URIs?
Option 1: To specify the version of IP addresses used for service URIs
Option 2: To provide a relative reference for resolving base URLs
Option 3: To indicate the preferred DNS messaging protocol
Option 4: To inform the UE (User Equipment) of the time until which the file repair server will be available
Explanation: The 'Availability-Time' attribute informs the UE of an absolute time (according to the UTC time standard) until which the UE can expect the file repair server to return the requested repair data, if reachable and functioning, ensuring the UE knows when to expect the service to be operational for repair data retrieval.