This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infeility (Eggs'plantation!), Subject name: Gynaecology & Obstetrics
[{'content': 'Endometrial biopsy for infeility test in women should be done at: \nSelect and explain. \nA. Ovulatory phase, B. Menstrual phase, C. Anytime during cycle, D. Premenstrual period', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Endometrial biopsy Best done preferably around 7 days before the onset of menstruation Secretory changes prove that the cycle has been ovulatory Can predict the functional integrity of the corpus luteum Can detect luteal phase defect', 'role': 'assistant'}]