Which force-related action is classified as unit self-defense?

Unit self-defense refers specifically to actions taken by a military unit as a whole in response to an external threat or attack. When a unit responds to a coordinated attack, it acts collectively to protect its members and maintain its operational integrity. This type of response is in line with the principles of military engagement, where the safety and effectiveness of the unit are paramount.

In contrast, actions like a soldier engaging in a fight or individual retaliation are focused on personal or isolated responses rather than coordinated unit activity. Similarly, personal defense during a civilian altercation does not involve a collective military response and is more about individual actions in a non-military context. Therefore, the response to a coordinated attack by the unit clearly aligns with the definition of unit self-defense, making it the correct choice in this scenario.