This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Haemophilus, Yersinia, Spirochaetes, Ricketssia, Chlamydia, Mycoplasma and Miscellaneous Bacteria), Subject name: Microbiology
[{'content': 'Which bacteria show this kind of growth pattern in Ghee broth \nSelect and explain. \nA. Yersinia Pestis, B. Acinetobacter, C. Aeromonas, D. Nocardia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In ghee broth , Yersinia pestis shows a characteristic growth which hangs down into broth from the surface , resembling stalactites ( stalactite growth )', 'role': 'assistant'}]