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: Unknown
[{'content': 'What is the effect of Progesterone-only pills? \nSelect and explain. \nA. Completely suppresses ovulation, B. Thin lining of uterus, C. Thick cervical mucus, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ref. KDT. Page. 343\nProgestogen-only pills have multiple biological effects on the female body.\nMultitude effect of POP:\n\nInhibition of follicular development\nInhibition of ovulation\nSuppression of corpus luteum formation\nChanges in the nature of the cervical mucus which inhibits the passage of sperms into the uterine cavity – Thickening of cervical mucous secretion\nEffects on the endometrium which affect implantation – by making it thin', 'role': 'assistant'}]