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
Tick born relapsing fever is/are caused by -a) Borrelia recurrentisb) Borrelia duttonii c) Borrelia burgdorferid) Borrelia hermsiie) None of above 
Select and explain. 
A. bd, B. d, C. ab, D. ac
A: bd
Answer: A: bd 
Explanation: None