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
Ductus arteriosus closes in response to: 
Select and explain. 
A. Decrease in peripheral oxygen saturation, B. Indomethacin therapy, C. Prostaglandin E1, D. Increase in pulmonary vascular resistance
B: Indomethacin therapy
Answer: B: Indomethacin therapy 
Explanation: 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.