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: Physiology
[{'content': 'Osteoclasts are inhibited / modified and regulated by: \nSelect and explain. \nA. Parathyroid hormone, B. Calcitonin, C. 1,25 - dihydroxycholecalciferol, D. Tumour necrosis factor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]