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': 'Cryosurgery is used in treatment of cervical intraepithelial neoplasia. It is appropriate in all except \nSelect and explain. \nA. Transformation zone lying entirely on ectocervix., B. Smooth cervical surface without deep crevices., C. Cervical intraepithelial neoplasia -3., D. CIN limited to two quadrants of the cervix.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Cryosurgery is generally not favoured for treatment of CIN-3 due to higher rates of disease persistence following treatment, and lack of histologic specimen to exclude occult invasive cancer.', 'role': 'assistant'}]