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: Surgery
Most common organism causing peritonitis is 
Select and explain. 
A. Klebsiella, B. E.coli, C. Staphylococcus aureus, D. Streptococcus
B: E.coli
Answer: B: E.coli 
Explanation: Most common cause of Peritonitis is E.coli 2nd most common cause is Klebsiella.