Your vessel is entering port when you change course and steady up on a range with the lights in line. After a few minutes you observe the range lights as shown in illustration D047NG below. How should your heading be altered?

Correct Answer: Option B — left, and when the range lights are in line again, steer to keep them in line fine on the starboard bow

Visual range interpretation per Bowditch indicates that if the upper mark moves to the port side while heading into port, the vessel has drifted to starboard, requiring a left course correction to re-establish the line.