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: Radiology
[{'content': 'Pneumatocele is commonest in: \nSelect and explain. \nA. Pneumococcal pneumonia, B. Staphylococcal pneumonia, C. H. influenzae pneumonia, D. Viral pneumonia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Staphylococcal pneumonia', 'role': 'assistant'}]