The correct answer is: A. Caution notice station.
A caution notice station is a station where the DRM (Divisional Railway Manager) has nominated a person to issue caution orders to train crew. This person is usually the station master or the assistant station master. The caution order is a document that is issued to the train crew to inform them of any potential hazards on the section of track that they are about to travel on. The caution order may include information about track work that is being done, speed restrictions, or other hazards.
The other options are incorrect because they do not accurately describe the person who is nominated by the DRM to issue caution orders to train crew. Option B, “Notice,” is too general. It does not specify who is responsible for issuing the notice. Option C, “Nil notice,” is incorrect because it does not refer to a person. Option D, “None of these,” is incorrect because it is not a valid option.