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': 'Swarming growth on culture is characteristic of which gram-negative organism? \nSelect and explain. \nA. Clostridium welchi, B. Clostridium tetani, C. Bacillus cereus, D. Proteus mirabilis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Proteus mirabilis swarming behavior is characterized by the development of concentric rings of growth that are formed as cyclic events of swarmer cell differentiation, swarming migration, and cellular differentiation are repeated during colony translocation across a surface.', 'role': 'assistant'}]