What light configuration must a vessel restricted in her ability to maneuver display at night?

Answer: C — Three vertical lights with red on top, white in the middle, and red on the bottom

A vessel restricted in her ability to maneuver must display three vertical lights at night: red on top, white in the middle, and red on the bottom. This configuration is specific to vessels that cannot maneuver as a result of their work or nature, such as those engaged in dredging, underwater operations, or servicing cables. The red lights at the top and bottom indicate the presence of a vessel that is restricted in its ability to maneuver, signaling to other vessels that they should proceed cautiously. The white light in the middle acts as a navigational light visible from all directions. This light configuration is essential for ensuring that other vessels can recognize the vessel's limitations and take appropriate action to avoid collisions. Understanding and following these signaling regulations is critical for maintaining safe navigation on the water.