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
Who discovered Treponema pallidum 
Select and explain. 
A. Schaudinn and Hoffmann, B. Paul Ehrilich, C. Roux and Yersin, D. Yersin and Kitasato
A: Schaudinn and Hoffmann
Answer: A: Schaudinn and Hoffmann 
Explanation: Schaudinn and Hoffmann discovered Treponema pallidum.