This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Medicine
[{'content': 'Period of isolation in salmonella infection is till: \nSelect and explain. \nA. 72 hours after chemotherapy, B. Widal negative, C. 3 consecutive stool cultures are negative, D. Urine culture is negative twice', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' 3 consecutive stool culture are negative The cases in typhoid infection are isolated till three bacteriologically negative stools and urine reports are obtained on three separate days.", 'role': 'assistant'}]