Refer to the exhibit. Which solution must be used to send traffic from the foreign wireless LAN controller to the anchor wireless LAN controller?

EoIP (Ethernet over IP) tunneling is the Cisco-native mobility mechanism used between foreign and anchor WLCs; it encapsulates the full Ethernet frame and preserves client MAC and VLAN context across Layer 3 network boundaries between the two controllers, enabling seamless roaming and centralized policy enforcement at the anchor.

MPLS VPN and VRF are Layer 3 routing and segmentation technologies, not the tunnel mechanism that WLCs use natively for foreign-to-anchor client traffic forwarding.

IPinIP and IPsec are general-purpose IP tunneling protocols not natively used by Cisco WLCs for the foreign-to-anchor mobility tunnel; Cisco WLCs specifically use EoIP for this purpose.

Sending traffic without encapsulation would strip the Layer 2 Ethernet context needed to deliver traffic to the correct client session on the anchor controller, and the two controllers may reside on different Layer 3 segments.