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: Social & Preventive Medicine
The following organism because of its easy culture methods is widely used as bacteriology' indicator of water polution- 
Select and explain. 
A. Foecal streptococci, B. Escherichia soli, C. Clostridium perfringens, D. Salmonella Typhi
B: Escherichia soli
Answer: B: Escherichia soli 
Explanation: Ans. is 'b' i.e., Escherichia coli