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': 'Colposcopy is best performed during \nSelect and explain. \nA. Proliferative phase, B. Secretory phase, C. Menstrual phase, D. Any day of cycle', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cervix is moist with mucus and external os is slightly patulous in proliferative phase and exposes squamocolumnar junction adequately.', 'role': 'assistant'}]