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: Pathology
In frey's syndrome, neurotransmitter is: 
Select and explain. 
A. Acetylcholine., B. Epinephrine., C. Norepinephrine., D. Serotonin.
A: Acetylcholine.
Answer: A: Acetylcholine. 
Explanation: None