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
All are true about the Widal test, except : 
Select and explain. 
A. Baseline differs depending on the endemicity of disease., B. O antibodies last longer and hence are not an indicator of recent infection, C. H antigen cannot differentiate between subtypes, D. High titre value in a single Widal test, not confirmation
B: O antibodies last longer and hence are not an indicator of recent infection
Answer: B: O antibodies last longer and hence are not an indicator of recent infection 
Explanation: None