Which of the following statements about 5G deployment option 3 is FALSE?

5G deployment Option 3 is a Non-Standalone (NSA) architecture, part of the E-UTRA-NR Dual Connectivity (EN-DC) framework. A defining characteristic of the entire Option 3 family (including variants 3, 3a, and 3x) is its reliance on the existing 4G Evolved Packet Core (EPC). The Master eNodeB (eNB) anchors the control plane to the EPC. Architectures that utilize the 5G Core (5GC), referred to as the next-generation core, are defined under different option numbers (e.g., Option 2 for Standalone, or Options 4 and 7 for NSA). Therefore, the statement that the core network for Option 3 may be a next-generation core is fundamentally false.

B. In the primary variants of Option 3 (and 3a), the eNB is the master node and anchors the user plane to the EPC's Serving Gateway via the S1-U interface. Thus, this statement is true.
C. The eNB, as the master node in Option 3/3a, maintains connections to the EPC for both the control plane (S1-MME) and the data plane (S1-U). This statement is true.
D. In the EN-DC architecture that defines Option 3, the X2 interface is specified for communication and data forwarding between the Master eNB and the Secondary gNB. This statement is true.

1. 3GPP TS 37.340 V17.4.0 (2022-06), "Evolved Universal Terrestrial Radio Access (E-UTRA) and NR; Multi-connectivity; Overall description; Stage 2".

Section 4.1.2, "EN-DC with EPC": This section explicitly defines the architecture for the Option 3 family. Figure 4.1.2-1 shows the overall architecture where the MeNB (eNB) connects to the EPC, and an X2 interface connects the MeNB to the SgNB (gNB). This confirms the core is EPC (making A false) and that an X2 interface exists (making D true).

Section 4.2.2, "User Plane for EN-DC with EPC": Figures 4.2.2-1 and 4.2.2-2 illustrate the user plane for MCG bearers and Split bearers in Option 3, respectively. Both show the S1-U (data plane) interface between the MeNB and the S-GW (part of EPC), confirming that statements B and C are true for this configuration.

2. Nokia White Paper, "5G Architecture" (2018).

Section "5G deployment options", pages 8-10: This document describes the 3GPP-defined deployment options. It clearly associates Option 3 (NSA) with the EPC and distinguishes it from options that use the 5G Core. It states, "In non-standalone mode, the initial deployments will be based on Option 3, where the EPC is the core network." This supports that statement A is false.