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': 'Salmonella typhi can be isolated at different times from \nSelect and explain. \nA. Feaces, B. Blood, C. Urine, D. All the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]