Final answer:
Reverend Ansel Bourne's case of dissociative fugue was unusual because he never recovered his memory and most individuals with this disorder don't adopt new identities.
Step-by-step explanation:
William James described a case of dissociative fugue in Reverend Ansel Bourne. The case was unusual compared to most modern cases of dissociative fugue because the reverend never recovered his memory (option B) and most individuals with dissociative fugue don't adopt new identities (option D). Dissociative fugue is a rare dissociative disorder characterized by sudden travel or wandering, during which the person may assume a new identity and have no memory of their previous life or personal information.