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: Gynaecology & Obstetrics
[{'content': "SERM's are used as add-back therapy concurrently with GnRH agonist to \nSelect and explain. \nA. Increase shrinkage of leiomyoma, B. Prevent bone loss, C. Avoid vasomotor symptoms, D. Decrease venous thromboembolism risks", 'role': 'user'}, {'content': 'Answer: B \nExplanation: SERMs  are used concurrently with GnRH agonist to prevent bone loss.', 'role': 'assistant'}]