Reviewing the history of your recently deceased 45-year-old patient, you notice that his dementia, personality changes, and physical limitations progressed in a stepwise fashion, with distinct...

Reviewing the history of your recently deceased 45-year-old patient, you notice that his dementia, personality changes, and physical limitations progressed in a stepwise fashion, with distinct declines in function every few months. What is the most likely cause of this rapidly progressing disease?

 A. AD

 B. Frontotemporal dementia

 C. vCJD

 D. Vascular dementia