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': 'Following grows in the cell free medium except - \nSelect and explain. \nA. Rickettsia, B. M leprae, C. Baonella, D. Syphilis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Rickettsiae cannot be grown in cell-free culture media. They usually grow in the cytoplasm of infected cells. REF:Textbook ofMicrobiologyy, Anantha Narayan, and Paniker. Page no.: 406', 'role': 'assistant'}]