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
[{'content': "The following organism because of its easy culture methods is widely used as bacteriology' indicator of water polution- \nSelect and explain. \nA. Foecal streptococci, B. Escherichia soli, C. Clostridium perfringens, D. Salmonella Typhi", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Escherichia coli", 'role': 'assistant'}]