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': 'Stalactite growth in ghee broth is due to - \nSelect and explain. \nA. H. influenza, B. C. diphtheria, C. Y pestis, D. T. pallidium', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]