What term refers to the plan of action for responding to enemy fire?

The term that best describes the plan of action for responding to enemy fire is "Battle Drill." Battle drills are predefined responses to specific situations that troops practice to ensure preparedness and effective reaction under fire. These drills provide a clear, organized approach for responding to threats and coordinating actions among unit members, allowing for rapid and efficient responses in high-stress combat scenarios.

While tactical maneuvers involve movement and positioning on the battlefield, they do not specifically focus on the immediate response to enemy fire. An engagement plan might refer to how forces will engage an enemy in a broader tactical sense but lacks the specificity of immediate actions dictated by battle drills. Fire control typically relates to the management of weapon systems and coordinating fire support rather than the holistic response actions to enemy fire. Therefore, "Battle Drill" is the most appropriate term for the action plan required in response to enemy attacks.