Final answer:
The ship needs a person who plots the course to navigate through a narrow rocky channel in foggy weather.
Step-by-step explanation:
The subject of this question is English since it is asking about the meaning of words and their role in a specific context.
The ship needing a good navigator in foggy weather indicates the importance of someone who can accurately plot the course to navigate through a narrow, rocky channel.
Out of the given options, the person who plots the course (option D) would be the ideal choice to help the ship safely pass through the channel.
Learn more about navigation on a ship