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: Pharmacology
Misoprostol is a : 
Select and explain. 
A. Prostaglandin E1 analogue, B. Prostaglandin E2 analogue, C. Prostaglandin antagonist, D. Antiprogestin
A: Prostaglandin E1 analogue
Answer: A: Prostaglandin E1 analogue 
Explanation: Natural prostaglandin in body is PGE2 whereas misoprostol and alprostadil are synthetic PGs which are PGE1 analogs.