BOTH INTERNATIONAL & INLAND Your vessel is underway but stopped and making no way through the water when fog sets in. Which fog signal should you sound?

Correct Answer: Option D — Two prolonged blasts on the whistle

Under Inland Navigation Rules, for the condition where 'Your vessel is underway but stopped and making no way through the water when fog sets in. Which fog signal should you sound', the correct requirement is: 'Two prolonged blasts on the whistle'. This standard ensures clear navigational intent and collision avoidance.