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: Physiology
[{'content': 'True statement regarding Nitric oxide is : \nSelect and explain. \nA. NO is synthesized from arginine, B. NO is spontaneous produced from NO2, C. NO causes vasoconstriction, D. NO is released from mitochondria', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. NO is synthesized from arginine', 'role': 'assistant'}]