What is the main role of camelbacks as mentioned in the Ranger Handbook?

The main role of camelbacks, as referenced in the Ranger Handbook, is to promote hydration. Hydration is crucial for maintaining optimal physical performance, especially during rigorous activities and in challenging environments typical for Rangers. A camelback, which is essentially a hydration pack, allows soldiers to easily carry water while keeping their hands free for other tasks. This accessibility is essential in the field where water sources may not be readily available, and quick hydration can significantly enhance endurance and decision-making capabilities during operations.

The focus on hydration is particularly vital in hot or arid conditions, where the risk of dehydration increases. Regular fluid intake directly supports physical and cognitive functions, ensuring that soldiers remain effective in their mission. While other items like ammunition or navigation tools are important, the primary function of camelbacks is their role in sustaining hydration, making option B the correct choice.