Which command is given to move one's arms down when transitioning in formation?

The command to move one's arms down when transitioning in formation is indeed indicated as the correct answer. This command clearly directs individuals to execute the movement of their arms downwards, which is an essential part of maintaining proper alignment and posture while in formation.

When soldiers are in formation, clear and concise commands are crucial for maintaining discipline and uniformity. By using the specific term "arms downward," the command ensures that everyone understands that they should lower their arms to a position that typically aligns with standing at attention or preparing for the next drill command. This level of precision is important in military formations to prevent confusion and ensure that movements are executed smoothly and in unison.

In contrast, the other commands are directed towards different movements or stances, which are not suitable for the action of lowering the arms. The focus on clarity in movement commands helps enhance the overall cohesiveness within the unit during transitions.