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': 'Widal test is specific for: \nSelect and explain. \nA. Plague, B. Leprosy, C. Pemphigoid, D. Typhoid', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]