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
The risk factors for placental abruption include the following except - 
Select and explain. 
A. History of placental abruption in previous pregnancy, B. Hypertension, C. Diabetes mellitus, D. Preterm rupture of membranes
C: Diabetes mellitus
Answer: C: Diabetes mellitus 
Explanation: Ans: C