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': 'Presence of it indicates remote contamination of water \nSelect and explain. \nA. Streptococci, B. Staphalococci, C. Clastridium pertringes, D. Nibrio', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]