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': 'Granulosa cell tumour secretes : \nSelect and explain. \nA. Progesterone, B. Oestrogen, C. HCG, D. Calcitonin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Oestrogen', 'role': 'assistant'}]