This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urethra and penis, Subject name: Surgery
Commonest organism giving rise to urinary tract infection: 
Select and explain. 
A. E. coli, B. Proteus, C. Staphylococcus, D. Streptococcus
A: E. coli
Answer: A: E. coli 
Explanation: - Most common hospital acquired infection- UTI- Most common organism responsible for UTI- E. coli