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: Pathology
[{'content': 'Kahn test is a: \nSelect and explain. \nA. Tube flocculation., B. Slide flocculation., C. Tube agglutination., D. Slide agglutination', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]