This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bones, Subject name: Pathology
[{'content': 'Osteoporosis is caused by all, except: \nSelect and explain. \nA. Corticosteroid, B. Oestradiol, C. Methotrexate, D. Chronic heparin therapy', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' OestradiolOestradiol is used to prevent osteoporosis.Other causes of osteoporosis have been discussed before.", 'role': 'assistant'}]