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: Anatomy
Blastocyst implantation close to internal os causes 
Select and explain. 
A. Placenta pre, B. Placenta percreta, C. Placenta increta, D. Abruptio Placenta
A: Placenta pre
Answer: A: Placenta pre 
Explanation: A i.e. Placenta pre- When the placenta is implanted paially or completely over the lower uterine segment, over and adjacent to the internal os, it is called placenta pre