In the context of an open ranks march, what does the fourth rank do?

In the context of an open ranks march, the fourth rank steps back. This movement is part of the overall formation adjustment that allows for proper spacing and alignment among the ranks.

When the formation is executed, the fourth rank typically occupies the rearmost position and is responsible for moving back to create additional space for the ranks in front, which could include ranks one through three moving forward to ensure visibility and organization in the overall formation. This step back ensures that all ranks maintain their designated positions while allowing the entire formation to remain balanced and orderly.

The other options reflect movements that would disrupt the formation or fail to achieve the correct spatial arrangement necessary for an open ranks march. By stepping back, the fourth rank fulfills its role in the formation effectively.