BOTH INTERNATIONAL & INLAND You hear the fog signal of another vessel forward of your beam. Risk of collision may exist. You MUST __________.

Correct Answer: Option C — take all way off, if necessary

Under Inland Navigation Rules, for the condition where 'You hear the fog signal of another vessel forward of your beam. Risk of collision may exist. You MUST', the correct requirement is: 'take all way off, if necessary'. This standard ensures clear navigational intent and collision avoidance.