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: Gynaecology & Obstetrics
Cystitis is most commonly caused by : 
Select and explain. 
A. E. coli, B. Pseudomonas, C. Proteus mirabilis, D. Neisseria gonorrhea
A: E. coli
Answer: A: E. coli 
Explanation: E. coli