Question: When a UE is in RRC_IDLE or RRC_INACTIVE and T331 is running, what triggers the update of `measIdleCarrierListEUTRA` within `VarMeasIdleConfig` if the UE is capable of idle/inactive measurements for E-UTRA?
Option 1: Receipt of an RRCConnectionReconfiguration message with updated measurement settings.
Option 2: Update of system information (e.g., SIB5) that includes `measIdleConfigSIB`, containing a new `measIdleCarrierListEUTRA`.
Option 3: Expiration of the T331 timer, prompting a refresh of all idle/inactive measurement configurations.
Option 4: Change in the UE's location, detected by cell (re)selection, without an update in system information.
Explanation: The update of `measIdleCarrierListEUTRA` within `VarMeasIdleConfig` is triggered when the UE receives an update of system information (e.g., SIB5) that includes `measIdleConfigSIB`, containing a new `measIdleCarrierListEUTRA`, for UEs capable of idle/inactive E-UTRA measurements.