This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Spirochetes, Subject name: Microbiology
[{'content': 'Treponema pallidum was discovered by: \nSelect and explain. \nA. Hillary and Mehoni, B. Hoffman and Shauddin, C. Warren and Marshall, D. Yersin and Kitasato', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans: b (Hoffman and shauddin) Ref: Ananthanarayan, 7th ed, p. 377Treponema pallidum was discovered by Hoffman and ShauddinWarren and Marshall discovered Helicobacter pylori (PGI Dec 2007)Yersin and Kitasato discovered plague bacilli', 'role': 'assistant'}]