Question: Which of the following best describes the primary purpose of the MBMS Session Stop procedure in the UTRAN Iu interface, as initiated by the Core Network (CN)?
Option 1: To establish a new MBMS RAB for an incoming multicast service and allocate necessary resources.
Option 2: To notify User Equipment (UEs) about the end of a given MBMS Session, releasing associated MBMS RAB and Iu signalling connections.
Option 3: To modify existing QoS parameters for ongoing MBMS sessions to adapt to changing network conditions.
Option 4: To request the Radio Network Controller (RNC) to prepare for a software update, temporarily halting all MBMS services.
Explanation: The correct answer aligns with the described purpose of the MBMS Session Stop procedure. This procedure informs UEs that an MBMS session has concluded and frees up resources by releasing the corresponding MBMS Radio Access Bearer (RAB) and Iu signalling connection, as initiated by the Core Network (CN).