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
Post zone phenomenon is due to 
Select and explain. 
A. Antigen excess, B. Antibody excess, C. Haptens, D. Equal Antigen & Antibody
A: Antigen excess
Answer: A: Antigen excess 
Explanation: Prozone - Antibodies are excess.
Postzone - Antigen excess.