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': 'Isolation in patient with Salmonellosis is done \nSelect and explain. \nA. Till fever subsides, B. Till 3 stool test are negative, C. Till Widal becomes negative, D. For 48 hrs of Chloramphenicol treatment', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]