What must hold-short lines require from pilots to be valid?

• A. Positive read-back or confirmation.
• B. No response required.
• C. Pilots should decide whether to respond.
• D. The hold-short line is optional.

Answer: (C)

Hold-short lines require a positive read-back or confirmation from the pilot to be valid. This ensures the controller and pilot are in clear agreement about the exact boundary and what is expected—stopping at the line and not crossing until cleared. In practice, when ATC says to hold short, the pilot repeats the instruction or otherwise confirms understanding (for example, “Holding short of Runway 27”). The controller then acknowledges, confirming mutual understanding. This communication step prevents misinterpretation that could lead to crossing the line at the wrong time or causing conflicts with other traffic.