Which of the following best defines the term "chock"?

Correct Answer: Option D — casting fitted at the side of a deck used as a fairlead

A chock is a heavy casting, usually mounted on the bulwark or deck edge, designed to serve as a fairlead for mooring lines. It prevents chafing and directs the line from the bitts to the dock, ensuring the mooring arrangement maintains proper geometry and protects the vessel's structure from excessive line tension.