This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pulmonary Tuberculosis and Lung Abscess, Subject name: Pathology
[{'content': 'In primary tuberculosis, all of the following may be seen except: \nSelect and explain. \nA. Cavitation, B. Caseation, C. Calcification, D. Langhans giant cell', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cavitation is seen when there has been a previous sensitization of the host resulting in caseous necrotic material being present which is discharged through the cavities. So, it is associated with secondary tuberculosis more frequently.', 'role': 'assistant'}]