Vessels engaged in fishing with purse seine gear may exhibit two yellow lights in a vertical line. Under what condition may these lights be shown, and how do they flash?

1. A. At all times when fishing; they flash simultaneously every two seconds
2. ✓ Only when hampered by fishing gear; they flash alternately every second with equal light and occultation durationCorrect
3. C. Only when making way; they flash alternately every two seconds
4. D. Only when at anchor; they flash simultaneously every second