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
Typhoid carriers are detected by following except ? 
Select and explain. 
A. Isolation of bacteria from urine, B. Isolation of bacteria from bile, C. Vi antigen, D. Widal test
D: Widal test
Answer: D: Widal test 
Explanation: Ans. is 'd' i.e., Widal test