Question: What is the primary purpose of the 'UE Status Update Confirmation' procedure initiated by the CRNC (Controlling RNC) towards the Node B in a UTRAN network?
Option 1: To inform Node B about UEs transitioning from CELL_FACH or URA_PCH state to CELL_DCH state, requiring E-RNTI reallocation.
Option 2: To request Node B to release one or several E-RNTIs for UEs no longer using them in CELL_FACH or URA_PCH states.
Option 3: To update Node B about changes in UE's QoS (Quality of Service) parameters for ongoing sessions in CELL_FACH state.
Option 4: To confirm successful handover of UEs from one Node B to another within the same RNC's control.
Explanation: The 'UE Status Update Confirmation' procedure is used for notifying the Node B to release E-RNTIs associated with UEs in CELL_FACH or URA_PCH states and no longer requiring these identifiers, ensuring efficient resource management by freeing up unused resources for other UEs.