What is the initial action taken in response to the command "Platoon, Attention"?

When given the command "Platoon, Attention," the appropriate response is to come to the position of Attention. This command signifies a directive for all members of the platoon to stand upright, with feet together and arms at the sides, signifying readiness and respect. This position is foundational in military drill, and it prepares the platoon for further commands or movements. It emphasizes discipline, posture, and alertness, which are key elements of military bearing.

The other options represent actions that do not align with the command given. For instance, standing at ease implies a more relaxed posture and is not the immediate response to the command to stand to attention. Sitting down is not a correct response to an attention command, as it contradicts the requirement for readiness and respect. Presenting arms is a more specific command that is typically given during ceremonies or honors and is not the initial action directed by "Platoon, Attention."