The correct answer is A) Stand on, leaving the buoy to your starboard. In this scenario, the green can buoy indicates the starboard side of the channel. When leaving a harbor in dense fog, the appropriate action is to proceed slowly and keep the buoy to your starboard (right) side. This ensures you are staying within the navigable channel and not running aground or colliding with other vessels or obstructions. The other options are incorrect because: B) Stopping to fix your position is not the best course of action when visibility is poor and you need to keep moving; C) Turning hard right could take you outside the channel; and D) Passing the buoy to port would place you outside the channel.