Question: What action(s) does a User Equipment (UE) take when an intra-RAT cell selection or reselection occurs while timer T331 is running, and the serving frequency matches a carrierFreq in the validityAreaList, but the physical cell identity doesn't match any entry in the associated validityCellList?
Option 1: Continue running timer T331 and perform measurements on neighboring cells.
Option 2: Stop timer T331 but continue with the current RRC connection.
Option 3: Initiate a handover to a cell with a matching physical cell identity in the validityCellList.
Option 4: Stop timer T331 and perform actions as specified for ending the procedure (e.g., concluding the process appropriately).
Explanation: According to specifications, if during an intra-RAT cell selection or reselection while T331 is running, the serving frequency matches a carrierFreq in the validityAreaList but the physical cell identity of the serving cell doesn't match any entry in the validityCellList, the UE must stop timer T331. Following this, the UE performs actions leading to the end of the procedure, ensuring proper handling of the RRC state and resource management.