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: Radiology
[{'content': 'Kerley-B lines are seen when pulmonary venous pressure is: \nSelect and explain. \nA. 5 mmHg, B. 10 mmHg, C. 20 mmHg, D. 40 mmHg', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. 20 mmHg', 'role': 'assistant'}]