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
Large antigen - antibody reaction is required to cause - 
Select and explain. 
A. Serum sickness, B. Ahus reaction, C. Uicaria, D. Anaphylactic-reaction
B: Ahus reaction
Answer: B: Ahus reaction 
Explanation: Ans. is 'b' i.e., Ahus reaction