This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Pediatrics
[{'content': 'Ductus arteriosus closes in response to: \nSelect and explain. \nA. Decrease in peripheral oxygen saturation, B. Indomethacin therapy, C. Prostaglandin E1, D. Increase in pulmonary vascular resistance', 'role': 'user'}, {'content': "Answer: B \nExplanation: b. Indomethacin therapy(Ref: Nelson's 20/e p 2197, Ghai 8/e p 417)Indomethacin, a Prostaglandin inhibitor is used in medical closure of Ductus arteriosus.", 'role': 'assistant'}]