This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
[{'content': 'Hepatitis B infectivity is indicated by \nSelect and explain. \nA. Anti-HBsAg, B. HBsAg + HBeAg, C. Anti-HBsAg - Anti-HBc, D. Anti-HBeAg + Anti-HBs Ag', 'role': 'user'}, {'content': 'Answer: B \nExplanation: .', 'role': 'assistant'}]