BOTH INTERNATIONAL & INLAND Underway at night, a vessel displaying the lights shown in illustration D062RR below is which of the following?

Correct Answer: Option A — under sail

COLREG Rule 25 outlines that a sailing vessel underway must exhibit sidelights and a sternlight. When under sail alone, propelling machinery must not be in use, and the display of only red, green, and white navigation lights confirms sailing status without masthead steaming lights.