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: Pathology
[{'content': "Centre of tubercular granuloma is formed by - \nSelect and explain. \nA. T-lymphocytes, B. B-lymphocytes, C. Langhan's giant cells, D. Necrotic zone", 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e.,Necrotic zone Tubercular granulomaTubercular granuloma contains mostly blood-derived macrophages, epithelioid cells (differentiated macrophages) and multinucleated giant cells (also known as Langhans giant cells), surrounded by T- lymphocytes.Caseous granulomas are typical of tuberculosis. These structures are formed by epithelioid macrophages surrounding a central cellular necrotic region with a rim of lymphocytes of the T- and B-cell types.", 'role': 'assistant'}]