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: Dental
A young man presents to the emergency department with a maculopapular rash 2 weeks after healing of a painless genital ulcer. The most likely etiological agent is – 
Select and explain. 
A. Treponema Pallidum, B. Treponema Pertenue, C. Chalmydia Trachomatis, D. None of the above
A: Treponema Pallidum
Answer: A: Treponema Pallidum 
Explanation: Development of maculopapular rash two weeks after having a painless genital ulcer(probably chancre) suggests a diagnosis of secondary syphilis caused by Treponema.pallidum