What command is used to configure the bandwidth of an interface?

The command used to configure the bandwidth of an interface in Cisco networking is indeed "bandwidth kilobits-per-second." This command is applied in interface configuration mode to specify the bandwidth that is advertised by the device to routing protocols. This setting does not affect the actual physical speed of the interface but rather informs routing protocols about the bandwidth of the link so that they can make informed decisions based on this value.

Using the bandwidth command is essential for dynamic routing protocols like OSPF or EIGRP, which calculate their metrics based on this value. By defining the bandwidth, network administrators can influence the choice of the best path through the network, especially in environments with links of varying speeds.

The other choices offered do not represent valid commands within Cisco IOS for configuring interface bandwidth, hence they would not achieve the intended result.