This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
[{'content': 'Pulmonary lymph flow rate is \nSelect and explain. \nA. 20 ml/hour, B. 40 ml/hour, C. 50 ml/hour, D. 60 ml/hour', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Pulmonary lymph flow rate is 20 ml per hour Ref: guyton and hall textbook of medical physiology 12 edition', 'role': 'assistant'}]