What indicates a buoy that should be left to port when entering from seaward? (U.S. Aids to Navigation System)

Correct Answer: Option C — Odd number

Under the U.S. Aids to Navigation System (USATONS), lateral marks follow the 'Red Right Returning' rule. When entering from seaward, port-side buoys are green and marked with odd numbers. Starboard-side buoys are red and marked with even numbers. Thus, an odd number identifies a buoy to be left to port.