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: Pediatrics
Which of the following are signs of neonatal respiratory distress syndrome – 
Select and explain. 
A. Intercostal retraction, B. RR > 60/ min, C. PH < 7.2, D. All of these
D: All of these
Answer: D: All of these 
Explanation: None