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
Kahn test is a: 
Select and explain. 
A. Tube flocculation., B. Slide flocculation., C. Tube agglutination., D. Slide agglutination
A: Tube flocculation.
Answer: A: Tube flocculation. 
Explanation: None