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 an example of.......... Test.: \nSelect and explain. \nA. Flocculation, B. Agglutination, C. Both, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Agglutination', 'role': 'assistant'}]