Final answer:
The correct answer is B) Mary's wish for him to visit her grave.
Step-by-step explanation:
The correct answer is B) Mary's wish for him to visit her grave.
In the given information, it is mentioned that Mary has died. 48 hours after her death, the one thing Crabbe obeyed was Mary's wish for him to visit her grave. This implies that Crabbe followed Mary's request to visit her grave within 48 hours of her death. The other options such as the doctor's prescription for grief medication, Mary's request to avoid the bar, and the lawyer's instructions for estate distribution are not mentioned in the given information.