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 most common site of puerperal infection is : \nSelect and explain. \nA. Episiotomy wound, B. Placental site, C. Vaginal laceration, D. Cervical laceration', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Placental site', 'role': 'assistant'}]