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': 'Cervical mucus has following properties except: \nSelect and explain. \nA. High oestrogen levels at midcycle make cervical mucus thick, B. Estrogen primed cervical mucus filters out non-sperm components of semen, C. Midcycle mucus creates a reservoir for sperm, D. Elevated oestrogen levels near ovulation increases sodium chloride concentration', 'role': 'user'}, {'content': 'Answer: A \nExplanation: High oestrogen levels at midcycle make cervical mucus thin and stretchy responsible for ferning pattern.', 'role': 'assistant'}]