17. Parkinson's disease is characterized by a range of motor symptoms and mainly caused by
(A) the loss of dopamine-producing nerve cells.
(B) the degeneration of the upper motor and lower motor neurons.
(C) rapid and uncoordinated electrical firing in the brain.
(D) autoimmune disease producing antibodies to the acetylcholine receptors on skeletal muscle fibers.
(E) imbalances of autonomic nervous system

(A) The loss of dop...