This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Embryology, Subject name: Anatomy
[{'content': 'Crescents are derived from: \nSelect and explain. \nA. Epithelial cells + fibrin + macrophage, B. Mesangium + fibrin + macrophage, C. Tubule + mesangium + fibrin, D. Mesangium + fibrin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a. Epithelial cells+fibrin+macrophageCrescents: Presence of two or more layers of cell in crescent shaped in periphery of the Bowmans capsule.They are derived from proliferating parietal cells and Podocytes.It also derived from recruitment of circulating monocytes, macrophages and neutrophils.The local proliferation occurs in the Bowmans capsule.Crescents are the hall mark of RPGN.', 'role': 'assistant'}]