An EtherChannel interface is a logical interface that consists of a bundle of individual Ethernet links that act as a single network link. An EtherChannel interface can increase the bandwidth and reliability of a network connection5.
On a Cisco Firepower 9300 appliance registered with an FMC for high availability, the network administrator must create the EtherChannel interface on the FXOS CLI. The FXOS is the operating system that runs on the Firepower 9300 chassis and provides hardware management functions such as interface configuration, power supply status, fan speed control, and so on6.
To create an EtherChannel interface on the FXOS CLI, the network administrator can follow these steps5:
* Connect to the FXOS CLI using SSH or console.
* Enter scope eth-uplink command to enter Ethernet uplink mode.
* Enter create port-channel command to create an EtherChannel interface.
* Enter a port-channel ID (1-48) and a mode (on or active) for the EtherChannel interface.
* Enter add interface command to add physical interfaces to the EtherChannel interface.
* Enter one or more interface IDs (for example, 1/1) for the physical interfaces.
* Enter commit-buffer command to save the changes.
The other options are incorrect because:
* The FMC CLI does not provide any commands to create an EtherChannel interface on a Firepower
9300 appliance. The FMC CLI is mainly used for managing FMC settings such as backup, restore, upgrade, troubleshoot, and so on7.
* The FTD CLI does not provide any commands to create an EtherChannel interface on a Firepower 9300 appliance. The FTD CLI is mainly used for managing FTD settings such as routing, NAT, VPN, access control, and so on8.
* The FMC GUI does not provide any options to create an EtherChannel interface on a Firepower 9300 appliance. The FMC GUI is mainly used for managing FTD policies such as access control, intrusion, file, malware, and so on9.

Reference: https://www.cisco.com/c/en/us/td/docs/security/firepower/601/configuration/guide/fpmc-config- guide-v601/fpmc-config-guide-v60_chapter_01100011.html#ID-2101-0000000e