You have two sites connected to an EVPN network.

EVPN, when used with VXLAN, leveragesBGP MPLS/VXLAN control plane mechanisms. To prevent overlapping IP prefixes between different tenants or sites, EVPN uses aRoute Distinguisher (RD).

“In EVPN-VXLAN, the route distinguisher (RD) makes routes unique when overlapping IP prefixes or MAC addresses are advertised between multiple tenants or sites.”

Option A(designated forwarder) applies to multi-homing in EVPN, not prefix uniqueness.

Option B(Layer 2 gateway) does not prevent IP overlap; it bridges VLANs.

Option D(ESI) is used for identifying multi-homed Ethernet segments, not to differentiate overlapping subnets.

Option C(Route Distinguisher) is correct, as it uniquely identifies routes even if the IP addresses are the same across sites.