This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Anatomy
Iloprost in pulmonary aerial hypeension is administered 
Select and explain. 
A. Intravenous, B. Intramuscular, C. Oral, D. Inhalation
D: Inhalation
Answer: D: Inhalation 
Explanation: Ref Harrison 19 th ed pg 1666 Iloprost is a prostacyclin analogue approved inhalation for treatment of pulmonary aerial hypeension (PAH) Epoprostinil as iv treprostinil as oral /iv/SC/inhalation.