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
Normal QRS duration at 1 year of age is 
Select and explain. 
A. 0.03-0.07 seconds, B. 0.04-0.08 seconds, C. 0.04-0.09 seconds, D. 0.06-0.09 seconds
B: 0.04-0.08 seconds
Answer: B: 0.04-0.08 seconds 
Explanation: Normal QRS duration at various age groups Age group QRS duration in seconds 0-6 months 0.03-0.07 (0.05) 1-5 yr 0.04-0.08 (0.06) 10-15 yr 0.04-0.09 (0.07) >15 yr 0.06-0.09 (0.08) Reference: Essential Paediatrics; O.P. Ghai; Page no: 459