This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
[{'content': 'Permanent carrier for HBV is - \nSelect and explain. \nA. > 6 months, B. > 1 month, C. > 1 year, D. > 2 year', 'role': 'user'}, {'content': 'Answer: A \nExplanation: <p> The persistent carrier state has been defined as the presence of HBsAg for more than 6 months. Reference:Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:213. <\\p>', 'role': 'assistant'}]