Which feature uses the cross-link between two redundant WAN Edges to provide transport redundancy?

TLOC extension is the correct answer because it enables two redundant WAN Edge devices to share their TLOCs (Transport Locators) over a direct cross-link. This allows one WAN Edge to use the transport connections of the other, providing transport redundancy and ensuring connectivity even if one device loses its direct WAN links. Quality of service (QoS) prioritizes traffic but doesn't provide transport redundancy. Zero-touch provisioning (ZTP) automates device onboarding but isn't related to transport redundancy. OMP (Overlay Management Protocol) is a control plane protocol that advertises routes and TLOCs, but TLOC extension is the specific feature that leverages OMP to achieve transport redundancy between paired WAN Edges.