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': 'Normal poal venous pressure is \nSelect and explain. \nA. 5-10 mmHg, B. 10-15 mmHg, C. 15-20 mmHg, D. 20-35 mmHg', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Poal venous pressure is normally about 10 mm Hg in humans, and hepatic venous pressure is approximately 5 mm Hg.Ref: Ganong&;s Review of medical physiology 25th edition. Page: 509', 'role': 'assistant'}]