Answer: D. They hung the Albatross around the Mariner’s neck.
We know that the crew believes the killing of the albatross to have been wrong because they decide to hung the albatross around the mariner's neck. After the mariner kills the animal, the crew believes this to be a wrong action because of how helpful and innocent the bird was. They eventually blame the mariner for all their misfortunes, believing it to be bad luck due to his reprehensible actions. As punishment, they force the man to wear the bid around his neck.