Buoys and day beacons exhibiting a yellow triangle or square painted on them are used __________.

Correct Answer: Option B — where the ICW and other waterways coincide

The Intracoastal Waterway (ICW) uses yellow symbols to distinguish its aids from those of other waterways. A yellow triangle or square indicates that the ICW and another waterway coincide, ensuring mariners can identify the correct route when multiple channels overlap, per USCG Light List and Chart No. 1.