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': "Endometrial hyperplasia is caused by : \nSelect and explain. \nA. Oestrogen, B. Smoking, C. Ovulation inducing drugs, D. Asherman's syndrome", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Oestrogen', 'role': 'assistant'}]