Question: In an IP Multimedia Subsystem (IMS) Collaborative Session, which action can be initiated by the Controller UE regarding media flows in the session it controls?
Option 1: Only modification of existing media flows on all involved UEs simultaneously
Option 2: Addition, modification, or release of a media flow on any Controllee UE already in the session
Option 3: Deletion of an entire Collaborative Session without notifying involved UEs
Option 4: Transfer of media control to a non-IMS compatible UE
Explanation: This is correct because, according to the defined roles and capabilities, the Controller UE has comprehensive control over the Collaborative Session it manages. This includes initiating changes to media flows such as adding new ones, modifying existing ones (e.g., changing media types or streams), or releasing (terminating) them on any of the UEs participating in the session. This level of granular control ensures the Controller UE can dynamically manage the session's composition and resources as needed.