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: Social & Preventive Medicine
[{'content': 'Trench fever is caused by: September 2004 \nSelect and explain. \nA. Rochalimaea quintana, B. Rickettsia prowazaki, C. Rickettsia akari, D. Rickettsia typhi', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A i.e. Rochalimaea quintana', 'role': 'assistant'}]