Your Great Uncle Ryan, at 70 Years of Age, Is

Multiple Choice

Your great uncle Ryan, at 70 years of age, is starting to show signs of memory problems. He has difficulty remembering where he left his wallet and keys and sometimes cannot recall the names of his grandkids. If you know he has a good diet and does not drink or smoke, what disorder can you definitively rule out?

A) Alzheimer's disease
B) Parkinson's disease
C) Huntington's disease
D) Korsakoff's syndrome