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 of the following is seen in dark field microscopy: September 2009 \nSelect and explain. \nA. Vibrio, B. Spirochaetes, C. Chlamydia, D. All of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: Spirochaetes', 'role': 'assistant'}]