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: Microbiology
[{'content': 'Typhoid carriers are detected by following except ? \nSelect and explain. \nA. Isolation of bacteria from urine, B. Isolation of bacteria from bile, C. Vi antigen, D. Widal test', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Widal test", 'role': 'assistant'}]