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: Gynaecology & Obstetrics
Prostaglandin used for cervical ripening? 
Select and explain. 
A. PG E1, B. PG E2, C. PGF2 -a, D. Oral Oxytocin
B: PG E2
Answer: B: PG E2 
Explanation: PG E2