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 implants are deficient in which enzyme \nSelect and explain. \nA. Aromatase, B. 17 β - hydroxysteroid dehydrogenase type 2, C. 17 β - hydroxysteroid dehydrogenose type 1, D. 17 α - hydroxylase', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 17\xa0β - hydroxysteroid dehydrogenase type 2,which\xa0inactivates estrogen is absent in endometrial implants.', 'role': 'assistant'}]