The correct answer is: 110 meters.
The automatic block system (ABS) is a railway signaling system that prevents trains from colliding by ensuring that there is always a safe distance between them. The ABS works by dividing the track into sections, or blocks, and then using signals to control the movement of trains into and out of each block.
The minimum safe distance between two trains is determined by a number of factors, including the speed of the trains, the type of track, and the braking distance of the trains. In general, the minimum safe distance is 110 meters.
Option A: 110 meters is the correct answer.
Option B: 120 meters is too long. The minimum safe distance is 110 meters.
Option C: 105 meters is too short. The minimum safe distance is 110 meters.
Option D: 115 meters is too long. The minimum safe distance is 110 meters.