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: Skin
A young man presents to the emergency depament with a maculopapular rash 2 weeks after healing of a painless genital ulcer. The most likely etiological agent is 
Select and explain. 
A. Treponemapallidum, B. Treponemapeunae, C. Chalmydia Trachomatis, D. Calymatobacter granulomatis
A: Treponemapallidum
Answer: A: Treponemapallidum 
Explanation: A i.e. Treponema pallidum Development of nonpruritic maculopapular rash (secondary syphilis) two weeks after heeling of painless genital ulcer (primary syphilis) suggest Treponema pailidium as an etiological aget.