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: Biochemistry
[{'content': 'Sources of the nitrogen in urea cycle are \nSelect and explain. \nA. Aspartate and ammonia, B. Glutamate and ammonia, C. Arginine and ammonia, D. Uric acid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Sources of Nitrogen in urea are ammonia and aspartate.', 'role': 'assistant'}]