Which of the following knots can be used as a quick-release knot?

The bowline knot is considered a quick-release knot due to its unique structure that forms a fixed loop at the end of a rope while maintaining the ability to be untied easily under load. This feature is particularly advantageous in emergency situations where a rapid release of tension is needed without risking entanglement or damage to the rope. The bowline does not jam under load, allowing it to be loosened with minimal effort, making it an excellent choice for rescue operations or other scenarios where efficiency is critical.

In contrast, the figure eight knot secures the rope but is not designed for quick release as it can jam tightly, especially when under strain. The Prusik knot is effective for climbing and climbing-related applications but is intentionally designed to grip under load, making it difficult to untie quickly. The half hitch is useful for securing a line but does not provide a reliable means for creating a quick-release loop on its own. Thus, the bowline stands out as the best choice for a quick-release knot, providing both security and ease of release in critical situations.