This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Antepaum Haemorrhage, Subject name: Gynaecology & Obstetrics
[{'content': 'Most common cause of placenta pre: \nSelect and explain. \nA. Myomectomy, B. Primigravida, C. Multigravida, D. Previous cesarean section', 'role': 'user'}, {'content': 'Answer: D \nExplanation: A history of prior cesarean section and uterine curettage are significantly associated in patients with placenta pre. Placenta pre is most commonly found in Multiparous but most common cause is Previous cesarean section.', 'role': 'assistant'}]