While receiving train on an obstructed line and danger signal must be shown to LP at A. 45 meters B. 30 meters C. 40 meters from obstruction D. None of these

The correct answer is: A. 45 meters.

The danger signal must be shown to the locomotive pilot (LP) at 45 meters from the obstruction. This is to ensure that the LP has enough time to stop the train safely.

The other options are incorrect because they are not the required distance from the obstruction.