This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
[{'content': 'Widal test is a type of? \nSelect and explain. \nA. Tube agglutination, B. Slide agglutination, C. Tube precipitation, D. Slide precipitation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Tube agglutinationRef: Textbook of Microbiology by Ananthanarayan and Paniker / 299', 'role': 'assistant'}]