Question 319Navigation General

The correct answer is B) lettered. Spherical buoys in the United States are often lettered to provide additional identification, as per the United States Coast Guard Aids to Navigation System. While spherical buoys may also be red, green, or numbered, the defining characteristic is that they are typically lettered to uniquely identify the buoy. The other answer choices, while potentially accurate for other types of buoys, do not specifically apply to the defining feature of a spherical buoy within the Coast Guard's system of aids to navigation.