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': 'The first change in precancerous lesion on colposcopy is \nSelect and explain. \nA. Mosaics, B. Puntation, C. Acetowhite lesions, D. Cork-screw vessels', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The first change in precancerous lesion is punctuation', 'role': 'assistant'}]