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': 'DUB is due to : \nSelect and explain. \nA. Endometriosis, B. Fibroid, C. Endometrial carcinoma, D. Irregular shedding of endometrium', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Irregular shedding of endometrium', 'role': 'assistant'}]