This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Musculoskeletal system, Subject name: Anatomy
[{'content': 'Osteoclast are stimulated by \nSelect and explain. \nA. Thyroxine, B. PTH, C. Calcitonin, D. Estrogen', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Refer Robbins page no 1207-1208 Parathyroid hormone related protein (PTHrP) is a local factor, expressed by perichondrial stromal cells and early proliferating chondrocytes, that activates the PTH receptor and maintains proliferation of chondrocytes.', 'role': 'assistant'}]