A lighted buoy to be left to starboard, when entering a U.S. port from seaward, shall have a __________.

Correct Answer: Option D — red light

Under the IALA-B system used in the United States, buoys to be left to starboard when entering from seaward are red and, if lighted, display a red light. This follows the 'red, right, returning' rule, which is fundamental to safe channel navigation in U.S. waters.