The correct answer is B) Inspection of the tail shaft liner. To inspect the tail shaft liner, the vessel must be dry-docked. This is because the tail shaft and its liner are located underneath the vessel, and access to this area is only possible when the vessel is out of the water. The tail shaft and its liner are critical components that must be regularly inspected to ensure the vessel's propulsion system is functioning properly and safely. The other options, such as inspecting the double bottoms (A), verifying load line measurements (C), and cleaning the hull (D), can be done without the need for dry-docking, as they can be accessed or performed while the vessel is afloat.