This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacillus, Subject name: Microbiology
[{'content': 'Medusa head colonies are seen in \nSelect and explain. \nA. Bacillus anthracis, B. Bacillus cereus, C. C. parvum, D. C. difficile', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Bacillus anthracis', 'role': 'assistant'}]