A 39 yr old man with Down syndrome has exhibited increasing forgetfulness and angry outbursts over the past several months. He has become neglectful of personal hygiene and has trouble finding items in his room. Which of the following conditions is the most likely cause of these problems?
A. Alzheimer"s disease
B. Cerebrovascular disease
C. Intracranial neoplasm
D. Human immunodeficiency virus
E. Thiamine deficiency

A. Alzheimer"s disease
B. Cerebrovascular disease
C. Intracranial neoplasm
D. Human immunodeficiency virus
E. Thiamine deficiency