正解:C
Cisco SD-WAN uses the Overlay Management Protocol to exchange control-plane information between WAN Edge routers and vSmart controllers. OMP advertises three major categories of routing information:
OMP routes, TLOC routes, and service routes. OMP routes represent reachability to prefixes in service VPNs, such as connected, static, OSPF, EIGRP, BGP, or other routes learned at the local site. TLOC routes describe transport locations, which bind a system IP, color, and encapsulation to a WAN transport attachment. Service routes indicate service insertion capabilities, such as firewalls or other network services that can be reached through a particular site. This separation allows Cisco SD-WAN to build a secure overlay over any public or private transport while keeping transport reachability, service-side prefixes, and inserted services distinct. The other answer choices use generic terms such as underlay, MPLS, Internet, backup, or primary routes, but those are not the formal OMP advertisement categories. Therefore, the correct answer is prefix, TLOC, and service.