This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
A lady presented with fever and rashes, she returned from the USA gives a history of exposure to ticks. Most probable diagnosis is 
Select and explain. 
A. Epidemic typhus, B. Scrub typhus, C. Rocky mountain fever, D. Oraya fever
C: Rocky mountain fever
Answer: C: Rocky mountain fever 
Explanation: Rocky mountain spotted fever caused by R.ricketsii is most serious type of spotted fever.it is prevalent in n.america and South America,transmitted by dermacabtor Andersoni and related sps of ticks Anantnarayan and paniker's 10th edition