Question 476Navigation General

The correct answer is B) 5-fathom curve. On nautical charts of U.S. waters, the magenta color is used to mark prohibited areas, such as restricted military zones or other areas where navigation is prohibited. Magenta is not used to mark the 5-fathom curve, which is a depth contour line representing areas with a depth of 5 fathoms (30 feet). Instead, the 5-fathom curve is typically shown on charts using a blue or black line. Lighted buoys and radio beacons are also not marked in magenta, but rather with their respective symbology and colors based on their characteristics.