The correct answer is: B. Facing point of concern line.
The competent Railway servant shall be appointed to show proceed hand signal while receive a train on obstructed line on calling-on signal at the facing point of the concern line. This is because the facing point is the point at which the train will be diverted from the main line to the obstructed line. The competent Railway servant will need to be at this point to ensure that the train is diverted safely and that there are no obstructions on the line.
Option A is incorrect because the 1st facing point of station is not the point at which the train will be diverted from the main line to the obstructed line.
Option C is incorrect because 45 meters beyond the obstruction is not the point at which the train will be diverted from the main line to the obstructed line.
Option D is incorrect because there is always a need for a competent Railway servant to show proceed hand signal while receive a train on obstructed line on calling-on signal.