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: Social & Preventive Medicine
[{'content': 'Drug of choice for carriers typhoid is: \nSelect and explain. \nA. Ampicillin, B. Chloramphenicol, C. Co-trimoxazole, D. Clindamycin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ampicillin', 'role': 'assistant'}]