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
[{'content': 'Alprostadil is not used for : \nSelect and explain. \nA. Erectile dysfunction, B. Pulmonary hypertension, C. Patent ductus arteriosus, D. Critical limb ischemia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Alprostadil is used to keep the ductus open and not\xa0for already patent ductus arteriosus.', 'role': 'assistant'}]