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
Which of the following is a flocculation test ? 
Select and explain. 
A. Widal test, B. Weil- felix test, C. VDRL, D. Paul- Bunnel test
C: VDRL
Answer: C: VDRL 
Explanation: Ans. is 'c' i.e., VDRL When instead of sedimenting, the precipitate remains suspended asfloccules, the reaction is known as flocculation ( instead of precipitation) Examples -) VDRL slide flocculation test and Kahn tube flocculation test for syphilis.