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
Causative agent of syphilis? 
Select and explain. 
A. Treponema peunae, B. Treponema endemicum, C. Treponema corateum, D. Treponema pallidum
D: Treponema pallidum
Answer: D: Treponema pallidum 
Explanation: Ans. is 'd' i.e., Treponema pallidum