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': "Eisenmenger's syndrome is characterized by all except \nSelect and explain. \nA. Cyanosis, B. Anemia, C. Pulmonary hypertension, D. Narrow split S2", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Polycythemia occurs in eisenmengers syndrome due to increased erythropoietin\xa0 produced as a result of increased deoxygenated blood.', 'role': 'assistant'}]