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': 'Carbon monoxide diffusion capacity decreases in all, Except - \nSelect and explain. \nA. Emphysema, B. Primary pulmonary hypertension, C. Alveolar haemorrhage, D. Infiltrative lung disease', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]