Under the IALA-A Buoyage System, when entering from seaward a lateral system buoy to be left to port may display which topmark shown in illustration D046NG below?

Correct Answer: Option B — B

In IALA Region A, the port side of a channel when entering from seaward is marked by red buoys. The designated topmark for a port hand buoy is a single red cylinder, which corresponds to illustration B in the standard IALA buoyage reference diagrams provided for this exam.