This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: A.N.S., Subject name: Pharmacology
[{'content': 'Neurotransmitter released in response to raised blood pressure: \nSelect and explain. \nA. Acetylcholine, B. Adrenaline, C. Dopamine, D. Nor-adrenaline', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. AcetylcholineWhenever blood pressure rises, there is reflex stimulation of baroreceptors. These release Ach and depress the heart.', 'role': 'assistant'}]