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: Surgery
[{'content': 'Commonest cause of lung abscess - \nSelect and explain. \nA. Aspiration, B. Hematogenous spread from distant site, C. Direct contact, D. Lymphatic spread', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Routes of infection to lung\n\nAspiration of organisms that colonize the oropharynx (MC)\nInhalation of infections, aerosols\nHematogenous dissemination from an extrapulmonary site.\nDirect inoculation (as in tracheal intubation or stab wounds)\nContiguous spread from an adjacent site of infection.', 'role': 'assistant'}]