Which command must be entered when a device is configured as an NTP server?

ntp master. IP services questions test the exact function of infrastructure services such as addressing, name resolution, time synchronization, logging, monitoring, and secure management. Cisco CCNA 200-301 v1.1 includes this topic under IP Services, so the answer must be validated against normal Cisco device behavior and the operational wording of the scenario. The key is not simply recognizing a familiar acronym; it is identifying what the feature does, where it is configured, and what result it produces. The distractors name valid services, but they provide a different service function from the one required in the prompt. In a real network, selecting the wrong option would either leave the feature nonfunctional, create a forwarding or security gap, or send troubleshooting in the wrong direction. The selected answer is the only one that matches the stated requirement and the way Cisco switching, routing, services, security, wireless, or automation functions are expected to operate. This is why the verified answer remains the best technical choice for the question.