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: Pharmacology
[{'content': 'Drug locally used for tracheal stenosis is : \nSelect and explain. \nA. Mitomycin C, B. Doxorubicin, C. Bleomycin, D. Clindamycin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]