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': 'Indication of fecal contamination of water is due to presence of all, EXCEPT: \nSelect and explain. \nA. Enterococci, B. Coliform, C. E.coli, D. Clostridium difficile', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The primary bacterial indicator recommended for this purpose is the coliform group of organism. Supplementary indicator organisms are: Fecal group: E.coli, Fecal streptococci and sulphite reducing bacteria Non Fecal group: Klebsiella aerogenes. Clostridium perfringens: The spores are capable of surviving in water for a longer time than organism of the coliform group & usually resistant chlorination. Ref: Park, 20th Edition, Page 630', 'role': 'assistant'}]