This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histamine, 5-HT and PGs, Subject name: Pharmacology
[{'content': 'prostacyclin agonist which is usually given oral. \nSelect and explain. \nA. Teleprost, B. Iloprost, C. Riociguat, D. Selexipag', 'role': 'user'}, {'content': 'Answer: D \nExplanation: * Selexipag is the only PGI2 drug which can be given oral route * Prostacyclin analogue like iloprost, treprostinil can be given i/v or s.c or inhaltional route.', 'role': 'assistant'}]