This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Legionella, Subject name: Microbiology
Pontiac fever is caused by? 
Select and explain. 
A. Legionella, B. Mycoplasma, C. Rickettsia, D. Salmonella
A: Legionella
Answer: A: Legionella 
Explanation: Ans. (a) LegionellaRef: BRS microbiology 4/e, p 50, Harrison's 17/e, chapter 141