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': 'Only certificate of vaccination required for international travel is \nSelect and explain. \nA. Hepatitis B, B. BCG, C. Tetanus, D. Yellow fever', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]