Refer to the exhibit. The CE router is peering with both PE routers and advertising a public prefix to the internet. Routing to and from this prefix will be asymmetric under certain network…

This option uses `reachable-via rx` (strict mode), which would drop packets if the reverse path is not through the ingress interface, directly conflicting with the requirement to allow asymmetric routing.

This option merely enters interface configuration mode and does not provide any uRPF (Unicast Reverse Path Forwarding) configuration.

This option, `allow-default`, permits traffic if the source IP is reachable via any interface or the default route. If the default route points to the internet, it could inadvertently permit RFC1918 traffic if no more specific route exists, violating the requirement to drop RFC1918 traffic.

The `ip verify unicast source reachable-via any` command ensures that a packet's source IP address exists in the FIB (Forwarding Information Base) as reachable via *any* interface. This prevents RFC1918 addresses from public-facing interfaces (as they wouldn't be in the FIB) while accommodating asymmetric routing paths by not requiring the reverse path to be the ingress interface.