This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lab Investigations, Subject name: Microbiology
[{'content': 'Which of the following test is the best diagnosis in a patient with typhoid? \nSelect and explain. \nA. Blood culture, B. Widal, C. Stool culture, D. Urine culture', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Other than a positive blood culture, no specific laboratory test is diagnostic for enteric fever. Option 2- The possible presence of cross reactive antibodies limits the use of serological test in the diagnosis of Salmonella. Option 3, 4: Stool/Urine culture can be used for typhoid carriers.', 'role': 'assistant'}]