Question: During an S1 handover in an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), what is primarily transferred from the source eNB to the target eNB via the MME using the MME Early Status Transfer procedure for each applicable E-RAB?
Option 1: UE: User Equipment's current location coordinates
Option 2: E-RAB: Evolved Radio Access Bearer setup configuration details
Option 3: Downlink SDU: Service Data Unit transmission failure records
Option 4: COUNT of the first downlink SDU for DAPS Handover or discarding already forwarded downlink SDUs
Explanation: The MME Early Status Transfer procedure ensures seamless E-UTRAN handovers by managing downlink Service Data Units (SDUs). It transfers the COUNT of the first downlink SDU for each applicable E-RAB, relevant to DAPS Handover, helping forward or discard already transmitted SDUs based on time triggers, ensuring data integrity and minimizing loss during eNB handovers.