The correct answer is B) location of the center of gravity of the light ship. The main purpose of the inclining experiment on a vessel is to determine the location of the center of gravity of the light ship, which is the ship without any cargo, fuel, water, stores, passengers, or crew on board. This information is critical for calculating the vessel's stability and ensuring it operates safely. The other answer choices are incorrect because: A) the position of the metacenter is not directly determined by the inclining experiment, but can be calculated from the results; C) the maximum load line is determined through other regulations and procedures; and D) the position of the center of buoyancy is not the main purpose of the inclining experiment.