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': '"Endemic" typhus is transmitted by: \nSelect and explain. \nA. Rickettsia prowazeki, B. Ricketssia mooseri, C. Ricketssia burnetti, D. Ehrilichia chafeensis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ricketssia mooseri', 'role': 'assistant'}]