The correct answer is C) 3 turns of wire normally mark either side of the detachable link 45 fathoms from the anchor. The reasoning is based on the standard regulations and practices for marking anchor rodes (the line or cable that connects the anchor to the vessel). Typically, three turns of wire are used to mark the 45-fathom point on the anchor rode, which helps the crew easily identify this critical location during anchor deployment and recovery. The other options are incorrect because 1 turn is too few, 2 turns is less common, and 4 turns would be excessive for this standard marking.