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': 'Strength of sewage is expressed in terms of all except \nSelect and explain. \nA. Suspended particles, B. E-Coli Count, C. Chemical oxygen demand, D. Biological oxygen demand', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]