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': 'Most common cause of menorrhagia in childbear-ing period: \nSelect and explain. \nA. Fibroid, B. Dysfunctional uterine bleeding, C. Pelvic endometriosis, D. Adenomyosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]