In the North Sea area, you sight a buoy with a quick light showing 3 flashes every 10 seconds. Which topmark in illustration D030NG below would be fitted to this buoy under the IALA Buoyage Systems?

Correct Answer: Option D — D

Under IALA Region A, a West Cardinal mark is identified by a quick or very quick light showing 9 flashes. However, a 3-flash sequence at 10-second intervals identifies an East Cardinal mark. The topmark for an East Cardinal consists of two cones base-to-base.