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
True about widal test 
Select and explain. 
A. Anti-O antibody persists longer, B. O antigen of S paratyphi is used., C. H-antigen is most immunogenic., D. Felix tube is used for H agglutination.
C: H-antigen is most immunogenic.
Answer: C: H-antigen is most immunogenic. 
Explanation: None