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': 'The most common cause of ronchopulmonary aspergillosis is - \nSelect and explain. \nA. Aspergillus fumigatus, B. Aspergillus clavatus, C. Aspergillus flavus, D. Aspergillus niger', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]