The correct answer is: A. DSO
A DSO, or Divisional Signalling Officer, is a railway employee who is responsible for the safe operation of railway signals and track circuits in a particular division. They are also responsible for issuing permits for trains to stop with a few passengers vehicles beyond platform.
A DRM, or Divisional Railway Manager, is a senior railway employee who is responsible for the overall management of a railway division. They are not responsible for issuing permits for trains to stop with a few passengers vehicles beyond platform.
A DOM, or Divisional Operating Manager, is a railway employee who is responsible for the day-to-day operation of a railway division. They are not responsible for issuing permits for trains to stop with a few passengers vehicles beyond platform.
In conclusion, the only person who can permit a passenger carrying train to stop with a few passengers vehicles beyond platform is a DSO.