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: Microbiology
[{'content': "`Malignant pustule' is - \nSelect and explain. \nA. Anthrax ulcer, B. Proliferating rodent ulcer, C. Malignant melanoma, D. Marjolin's ulcer", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]