The correct answer is B. 02.
The absolute block system is a system of mine safety that uses detonators to create a series of small explosions that break up the rock face. The detonators are placed 10 meters apart, and the first detonator is placed 1200 meters from the obstruction guard. This ensures that the rock face is broken up evenly and that there is no risk of a large explosion.
Option A is incorrect because it would result in the detonators being placed too close together. This could cause a large explosion that could damage the mine or injure the workers.
Option C is incorrect because it would result in the detonators being placed too far apart. This could cause the rock face to not be broken up evenly, which could lead to a collapse.
Option D is incorrect because it is not a valid option.