This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Biochemical etiology of Alzheimer's disease relates to 
Select and explain. 
A. Serotonin, B. Dopamine, C. Acetylcholine, D. GABA
C: Acetylcholine
Answer: C: Acetylcholine 
Explanation: Neurotransmitters, which are decreased in Alzheimer's disease:- Acetylcholine (most important), norepinephrine, somatostatin, corticotropin.