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: Pharmacology
[{'content': 'Major estrogen in normal adult women is - \nSelect and explain. \nA. Estradiol, B. Estrone, C. Estriol, D. None of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Estradiol o Estradiol is the major estrogen secreted by the ovary.", 'role': 'assistant'}]