This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'Medusahead colonies on nutrient agar point the diagnosis of infection with \nSelect and explain. \nA. Bacillus anthracis, B. Bacillus cereus, C. Anthracoid bacilli, D. Clostridium per fringes', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Bacillus anthracis-medusa hair appearance like growth on nutrient agar Ref: Textbook of Microbiology Baveja 5th ed Pg 220', 'role': 'assistant'}]