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: Medicine
[{'content': 'True about polycythemia rubra vera is all except - \nSelect and explain. \nA. Bleeding, B. Thrombosis, C. ↓ed ESR, D. Infection', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]