Final answer:
The PSG's primary role during movement and halts is to coordinate communication across the platoon, ensuring that orders and information are effectively relayed.
Step-by-step explanation:
During movement and halts, the PSG (Platoon Sergeant) primarily performs the role of coordinating communication. The PSG ensures effective communication among various units and leaders, maintains situational awareness, and helps relay commands and information crucial for the platoon’s operations. While the PSG might assist with logistics or tactical operations, their main responsibility is to maintain communication, making option (d) the correct answer.