Which command lets you configure multiple interfaces at the same time?

The command that allows for the configuration of multiple interfaces simultaneously is known as "interface range." This command is particularly useful in scenarios where you want to apply the same configuration settings to a group of interfaces, such as FastEthernet or GigabitEthernet ports, without having to configure each interface individually.

For instance, if you have several switches and you want to enable port security on multiple interfaces, you can enter the interface range command followed by the interface range (like interface range GigabitEthernet0/1 - 10) and then apply the desired configuration commands. This streamlines the process and saves time, especially in larger network environments with many interfaces.

The other options refer to commands or terminologies that are not recognized in Cisco IOS, making them invalid choices. Therefore, "interface range" is the correct and most efficient command for configuring multiple interfaces at once.