The correct answer is: A. Railway Board.
The Railway Board is the highest executive authority of the Indian Railways. It is responsible for the overall planning, coordination, and management of the railways. The Railway Board is headed by the Chairman, who is appointed by the President of India. The Railway Board has a number of members, who are also appointed by the President of India. The members of the Railway Board are responsible for different aspects of the railways, such as operations, finance, and personnel.
The Railway Board is responsible for issuing special instructions to be issued with the prior approval of the Railway Board. These instructions are issued to ensure the safety and efficiency of the railways. The Railway Board also has the power to amend or revoke these instructions.
The other options are incorrect.
Option B: CRS is the Chief Railway Safety Officer. The CRS is responsible for ensuring the safety of the railways. The CRS is appointed by the Railway Board. The CRS has the power to investigate accidents and recommend measures to prevent accidents.
Option C: CSO is the Chief Signal and Telegraph Officer. The CSO is responsible for the signaling and telegraph system of the railways. The CSO is appointed by the Railway Board. The CSO has the power to investigate accidents and recommend measures to prevent accidents.
Option D: None of these is the correct answer.