This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: general microbiology, 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: Pr.mirfabilis & Pr.vulgaris swarms on solid culture media .discrete colonies are seen in young cultures but thereafter actively motile cells spread on the surface of the plate in successive waves to form a thin film layer in concentric circles. REF:Ananthanarayan & Panicker's Textbook of Microbiology 8th edition pg no:280-281", 'role': 'assistant'}]