The correct answer is B) Wire must be of the stranded copper type. Electrical wiring used aboard vessels must meet specific requirements set by the US Coast Guard and other maritime regulations. One of these requirements is that the wire must be of the stranded copper type, as opposed to solid copper. Stranded wire is more flexible and durable, making it better suited for the dynamic environment of a vessel compared to rigid solid wire. The other answer choices are incorrect. A) is incorrect because wiring must be properly enclosed and insulated. C) is incorrect because the minimum wire size is not always 14 AWG, as it can vary depending on the specific application and location. D) is incorrect because solid copper wire is not the required type for marine applications.