The correct answer indicates that every 25 feet of Rapid Intervention Crew (RIC) line is marked with knots and a ring. This marking system is crucial for ensuring visibility and quick identification of the length of the line during operations.
The knots and rings serve as tactile indicators that allow firefighters to quickly gauge how much line has been deployed without needing to look. This becomes especially important in dark, smoky, or chaotic environments where visibility is limited. By following this standardized marking, responders can effectively control their movements and utilize the RIC line for rescue operations, ensuring everyone's safety.
Each of the other lengths mentioned, such as 10, 20, or 30 feet, do not align with the established protocols for RIC line marking. Using the correct interval for markings ensures consistency in emergency response teams and enhances operational efficiency.