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': 'Bagassosis is occupational lung disease caused by: \nSelect and explain. \nA. Carbon dioxide., B. Sugarcane dust., C. Cotton fibre particles., D. Mouldy hay.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]