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: Social & Preventive Medicine
Which of the following does not have non-human reservoir -a)  Salmonella typhib)  N. Gonorrhoeac)  E colid)  Clostridium tetani e)  Treponema pallidum 
Select and explain. 
A. ed, B. dca, C. abe, D. ac
C: abe
Answer: C: abe 
Explanation: None