The correct answer is B) main switchboard. The main switchboard is the central component of the shipboard electrical system used to control the distribution of power to the various branch circuits on the vessel. It serves as the primary distribution point for the electrical power generated by the ship's electrical system, allowing the crew to monitor and control the flow of electricity to different areas of the ship as needed. The other answer choices are incorrect because: A) Disconnect links are not used to control power distribution, but rather to isolate or disconnect specific circuits or equipment. C) The governor relay box is part of the engine control system, not the electrical distribution system. D) The bridge control panel is used for monitoring and controlling the ship's navigation and propulsion systems, not the electrical distribution.