This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neonatal Resuscitation, Subject name: Pediatrics
Resuscitation of term neonates should be initiated with how much oxygen concentration, if they require positive pressure ventilation? 
Select and explain. 
A. 100%, B. 50%, C. 30%, D. 21%
D: 21%
Answer: D: 21% 
Explanation: Resuscitation of term neonates- initiated with room air (21 % O2) Preterm neonates- 21 to 30% O2 (intermediate concentration)