正解:A
The verified answer is A. The default-router command in a Cisco DHCP pool supplies the default gateway option to DHCP clients. Clients receive that address as the router to use for destinations outside their local subnet. Cisco CCNA 200-301 v1.1 places this skill in IP Services, where the exam expects a working understanding of how the feature behaves on real Cisco networks, not just a memorized command. default- gateway is used differently on some switches, ip helper-address relays DHCP, and dns-server supplies name- resolution servers. In production, this distinction matters because a misapplied command or design choice usually creates an outage, a security gap, or unnecessary troubleshooting noise. The correct choice matches the control-plane, data-plane, wireless, security, or services behaviour described in the scenario and should be preferred over options that merely sound related.