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
Alprostadil is not used for : 
Select and explain. 
A. Erectile dysfunction, B. Pulmonary hypertension, C. Patent ductus arteriosus, D. Critical limb ischemia
C: Patent ductus arteriosus
Answer: C: Patent ductus arteriosus 
Explanation: Alprostadil is used to keep the ductus open and not for already patent ductus arteriosus.