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: Medicine
[{'content': 'Which of the following infection is most commonly related to aplastic anemia? \nSelect and explain. \nA. Hepatitis, B. H. pylori infection, C. Tetanus, D. Bacteremia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hepatitis is the most common preceding infection and posthepatitis marrow failure accounts for approximately 5% of etiologies in most series.', 'role': 'assistant'}]