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
Which rickettesiae are able to grow in cell free media - 
Select and explain. 
A. R. Quintana, B. R. Rickettsii, C. R. Typhi, D. R. Tsutsugamushi
A: R. Quintana
Answer: A: R. Quintana 
Explanation: None