A network engineer is configuring a new router at a branch office. The router is connected to an upstream WAN network that allows the branch to communicate with the head office. The central time serve

The `ntp server 172.24.54.8` command configures the router to act as an NTP client, enabling it to send requests to the specified IP address (172.24.54.8) and synchronize its clock with that authoritative NTP server. This is the standard method for a device to obtain time from an external source.

The `ntp master` command configures the router itself to act as an authoritative NTP server for other devices, not to synchronize with an upstream server.

The `ntp peer` command establishes a peer relationship where both devices can synchronize with each other, which is different from a client-server relationship with a primary time source.

`ntp client` is not a valid command on Cisco IOS devices for specifying a server; the `ntp server` command implicitly places the device into client mode.