Router R1 must send all traffic without a matching routing-table entry to 192.

The task describes a default route. A router uses a default route when no more specific route matches the destination address in the routing table. In IPv4, the static default route is written with destination 0.0.0.0 and mask 0.0.0.0, followed by the next-hop IP address or exit interface. Since the router must forward unmatched traffic to 192.168.1.1, the correct configuration is the option that uses ip route 0.0.0.0 0.0.0.0 192.168.1.1. Cisco CCNA 200-301 v1.1 IP Connectivity requires engineers to recognize default routes because they are common at branch routers, internet edges, and lab topologies. A route to a specific network would not satisfy the requirement to forward all unmatched traffic. A default gateway command is for switches or hosts in limited contexts, not the proper router forwarding-table method here. The answer is C because it represents the static default route toward 192.168.1.1.