Which of the following tools can also serve as a hydrant wrench?

The Hux Bar is designed with features that make it suitable for use as a hydrant wrench. Specifically, its shape and construction allow it to fit onto hydrant heads effectively, enabling firefighters to open and close hydrants when necessary. The design includes a specialized head that can grip the various sizes of hydrant fittings, making it versatile for different hydrant types. This functionality is essential for quickly establishing water supply during firefighting operations.

In contrast, the other tools listed have different primary functions. The Kelly tool is mainly used for prying and gripping, the Clemens hook is typically employed for handling and pulling items, and the Halligan tool is primarily a forcible entry tool designed to open locked doors and windows. While these tools may possess multiple uses in various scenarios, they are not specifically designed for operating hydrants like the Hux Bar. This specialization is what distinguishes the Hux Bar as an appropriate choice for this particular function.