BOTH INTERNATIONAL & INLAND When underway in restricted visibility, you might hear, at intervals of two minutes, any of the following fog signals EXCEPT __________.

Correct Answer: Option D — ringing of a bell for five seconds

Under Inland Navigation Rules, for the condition where 'When underway in restricted visibility, you might hear, at intervals of two minutes, any of the following fog signals EXCEPT', the correct requirement is: 'ringing of a bell for five seconds'. This standard ensures clear navigational intent and collision avoidance.