Question: What triggers the attempt of an outgoing handover when DRX is not used in E-UTRAN?
Option 1: Transmission of the RRCConnectionReconfiguration message to UE
Option 2: Receipt of the HandoverRequest message from the target eNodeB
Option 3: Expiration of the handover timer in the source eNodeB
Option 4: Detection of a better signal quality from a neighboring cell
Explanation: According to the 3GPP specification, the transmission of the RRCConnectionReconfiguration message to UE triggers the attempt of an outgoing handover when DRX is not used. This message indicates to the UE that it should perform a handover to a target cell.