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': 'Which rickettesiae are able to grow in cell free media - \nSelect and explain. \nA. R. Quintana, B. R. Rickettsii, C. R. Typhi, D. R. Tsutsugamushi', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]