Final answer:
The correct answer is option D: All of the above. Buoys with even numbers are typically used on the starboard side when entering from seaward or upstream.
Step-by-step explanation:
In the context of navigation and maritime safety, buoys are used as visual aids to mark channels, hazards, or specific areas in bodies of water. The question asks about which buoy may be even numbered, and the correct answer is option D: All of the above.
The numbering of buoys is a standardized system that helps mariners accurately navigate waterways. Buoys with even numbers are typically used on the starboard (right) side when entering from seaward or upstream.
For example, a lighted green buoy can be even numbered to indicate the presence of a safe channel or fairway on the starboard side. Similarly, a mid-channel buoy or an unlighted nun buoy can also have even numbers if they serve the purpose of marking the starboard side of a navigable channel.