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': 'Preferred bacteriological indicator of faecal contamination of water: March 2012 \nSelect and explain. \nA. Faecal streptococci, B. Cl. prefringens, C. Faecal staphylococci, D. E.coli', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans: D i.e. E. coli The primary bacterial indicator recommended for acceptability purpose is the coliform group of organisms as a whole. The coliform group includes both faecal (E.coli) and non faecal organisms (Klebsiella aerogens) Supplementary indicator organisms, such as faecal streptococci and sulphite-reducing clostridia, may sometimes be useful in determining the origin of faecal pollution as well as in assessing the efficiency of water treatment processes.', 'role': 'assistant'}]