BOTH INTERNATIONAL & INLAND A vessel may use any sound or light signals to attract the attention of another vessel as long as __________.

Correct Answer: Option A — the signal cannot be mistaken for a signal authorized by the Rules

Under Inland Navigation Rules, for the condition where 'A vessel may use any sound or light signals to attract the attention of another vessel as long as', the correct requirement is: 'the signal cannot be mistaken for a signal authorized by the Rules'. This standard ensures clear navigational intent and collision avoidance.