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': 'Major risk factor for development of lung abscess is: \nSelect and explain. \nA. Pneumonia, B. Aspiration, C. Lung cancer, D. Tuberculosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The major risk factor for primary lung abscesses is aspiration. Patients at particular risk for aspirationsuch as those with altered mental status,\xa0alcoholism, drug overdose, seizures,\xa0bulbar dysfunction,\xa0prior cerebrovascular or cardiovascular events, or neuromuscular disease,\xa0are most commonly affected.\xa0\n\nLung abscesses are usually characterized as either primary (~80% of cases) or secondary.\xa0\nPrimary lung abscesses usually arise from aspiration, are often caused principally by anaerobic bacteria, and occur in the absence of an underlying pulmonary or systemic condition.\xa0\nSecondary lung abscesses arise in the setting of an underlying condition, such\xa0as\xa0a\xa0post obstructive\xa0process\xa0 (e.g.,\xa0a\xa0bronchial\xa0foreign\xa0body\xa0or tumour) or a systemic process (e.g., HIV infection or another immunocompromising condition).\xa0\nLung abscesses can also be characterized as acute (<4–6 weeks in duration) or chronic (~40% of cases).\n\nReference: Harrison’s PRINCIPLES\xa0OF INTERNAL MEDICINE 20th edition page no 919', 'role': 'assistant'}]