The correct answer is A) at the anchor end of the line. When a combination chain and wire rope mooring line is used, the chain is deployed at the anchor end of the line. This is because the chain provides weight and durability at the anchor end, which helps to secure the mooring and prevent the line from being pulled from the anchor. The wire rope portion of the line is more flexible and better suited for the wildcat (or winch) end, where it can be easily handled and deployed. The other answer choices are incorrect because: B) placing the chain at the wildcat end would make the line more difficult to handle and secure; C) placing the chain midway would not provide the necessary weight and durability at the anchor end; and D) the chain is not deployed through the anchor buoy, but rather directly attached to the anchor.