The correct option is A Acetylcholine
Alzheimer’s disease in humans is caused by reduced synthesis of the neurotransmitter acetylcholine. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems with language, disorientation (including easily getting lost), mood swings, loss of motivation, not managing self-care, and behavioural issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death.