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 welchii, B. Clostridium tetani, C. Bacillus cereus, D. Proteus mirabilis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]