A lorry shall be protected by banner flags and detonators if it remains stationary within the station yard for more than A. 15 meters B. 10 meters C. 20 meters D. None of these

The correct answer is: A. 15 meters.

A lorry shall be protected by banner flags and detonators if it remains stationary within the station yard for more than 15 meters. This is to ensure the safety of the public and to prevent accidents.

The banner flags are used to warn people that there is a stationary lorry ahead. The detonators are used to create a loud noise that will alert people to the danger.

It is important to follow these safety precautions to prevent accidents.