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
Following reactions are produced by heterophile antigens, except 
Select and explain. 
A. Forssman antigen antibody reaction, B. Weil-Felix reaction, C. Paul bunnel reaction, D. Widal reaction
D: Widal reaction
Answer: D: Widal reaction 
Explanation: None