This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'At systemic aerial mean BP of 50 mmhg urine output is: \nSelect and explain. \nA. Nil, B. 0.5 ml/min, C. 1ml/min, D. 2ml/min', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref: graph fig:42.5 page no :356 Textbook of physiology Volume 1 7th edition AK Jain', 'role': 'assistant'}]