180 meters
600 meters
820 meters
1220 meters
Answer is Right!
Answer is Wrong!
The correct answer is B. 600 meters.
The final detonator is used to defend the train in broad gauge by detonating the explosive charge at a distance of 600 meters from the train. This distance is sufficient to ensure that the train is not damaged by the blast.
The other options are incorrect because they are not distances that are sufficient to protect the train from the blast. Option A, 180 meters, is too close and would likely result in damage to the train. Option C, 820 meters, is further away but may not be enough to protect the train from a powerful blast. Option D, 1220 meters, is a safe distance but would require the train to travel for a longer period of time before it is safe to detonate the explosive charge.