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: Unknown
[{'content': 'Carbamoyl phosphate synthase - 1 acts on - \nSelect and explain. \nA. Ornithine, B. Carbamoyl phosphate, C. CO2 & ammonia, D. Arginine', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e, CO2 & ammonia o Explained", 'role': 'assistant'}]