Question 663 Rules of the Road

The correct answer is C) to any condition where visibility is restricted. The term "restricted visibility" as used in the International and Inland Navigation Rules refers to any condition where visibility is reduced, not just to visibility of less than one-half mile or to fog specifically. The rules define restricted visibility as any condition in which the visibility is reduced due to fog, mist, falling snow, heavy rainstorms, sandstorms, or any other similar causes. The other answer choices are incorrect because they either limit the definition too narrowly (A and B) or introduce an additional criterion not specified in the rules (D).