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: Medicine
[{'content': 'Diffusion capacity of lung is increased by? \nSelect and explain. \nA. CHF, B. Pulmonary embolism, C. Chronic lung disease, D. Anemia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: DLCO increased in mild CHF,alveolar hemorrhage,polycythemia,left to right shunts.', 'role': 'assistant'}]