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: Unknown
Which of the following predisposes to placenta previa? 
Select and explain. 
A. Primigravida, B. Singleton pregnancy, C. Diabetesmellitus, D. Past cesarean pregnancy
D: Past cesarean pregnancy
Answer: D: Past cesarean pregnancy 
Explanation: Ans: D