Question 209Navigation General

The correct answer is D) safe water. According to the U.S. Aids to Navigation System, a lighted buoy with a spherical topmark marks safe water, which is the deepest part of the channel or fairway where vessels can safely navigate. The spherical topmark is a distinct visual cue that helps mariners identify this type of buoy. The other answer choices are incorrect because: A) port-side markers have a different shape (can or nun), B) underwater cables are not typically marked with buoys, and C) hazards to navigation are marked with different topmarks, such as a conical or pillar shape.