What should drivers do upon hearing the phrase "hold short" from ATC?

Answer: B — Stop before the runway hold line and wait for further instructions

When drivers hear the phrase "hold short" from Air Traffic Control (ATC), they must stop before reaching the runway hold line and wait for further instructions. This command is crucial for maintaining the safety of operations at the airfield, as it prevents vehicles from encroaching into active runway areas where aircraft may be taking off or landing. By stopping at the hold line, drivers allow ATC to manage airport traffic effectively, minimizing the risk of runway incursions, which can lead to serious accidents. Understanding the importance of this command helps ensure that drivers are always aware of their positioning relative to active runways and the need for vigilant communication with ATC for safe driving practices on the airfield.