This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
[{'content': 'Prozone phenomenon is due to \nSelect and explain. \nA. Antigen excess, B. Antibody excess, C. False +ve reaction, D. False -ve reaction', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Zone phenomenon (seen in agglutination and precipitation) consists of 3 pas: Prozone = Ab excess = weak or absent precipitation reaction = False -ve Zone of equivalence = peak amount of precipitation. Post zone = Ag excess = weak or absent precipitation reaction. REF : ananthanarayana 10th ed', 'role': 'assistant'}]