This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'Placenta accreta is associated with: \nSelect and explain. \nA. Placenta pre, B. Uterine scar, C. Multiple pregnancy, D. Multipara', 'role': 'user'}, {'content': 'Answer: B \nExplanation: <p> Placenta accreta is associated with a previous cesarean section scar or any other uterine incision or after uterine curettage. Reference:Mudaliar and Menon&;s clinical obstetrics,12th edition,page no:330 <\\p>', 'role': 'assistant'}]