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
Epidemic typhus causes & vector 
Select and explain. 
A. R. typhi & mite, B. Rickettessia prowazki & louse, C. R. conori & tick, D. R. akari & mite
B: Rickettessia prowazki & louse
Answer: B: Rickettessia prowazki & louse 
Explanation: None