BOTH INTERNATIONAL & INLAND What is required of a vessel navigating near an area of restricted visibility?

Correct Answer: Option D — All of the above

Rule 19 mandates comprehensive precautions in restricted visibility. This includes maintaining safe speed (Rule 6), having engines ready for immediate maneuver (Rule 19(b)), determining risk of collision via radar (Rule 7), and sounding appropriate fog signals (Rule 35). All these actions are required to ensure safety in low visibility.