A. When NR coverage is good, data packets of bearers that use dual connectivity are sent from EPC to UE using secondary cell group bearers.

B. When NR coverage is poor, data packets of bearers that use dual connectivity are sent to the UE through eNB.

C. Data packets of bearers that do not use dual connectivity are sent from EPC to UE through eNB.

D. When NR coverage degrades, the gNB decides when to use split bearers and send some of the packets received from the core through eNB.