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: Medicine
[{'content': 'The most dependable definitive diagnosis of typhoid is by: \nSelect and explain. \nA. Blood culture, B. Wide test, C. Bone marrow culture, D. Stool culture', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]