Which of the following age range is classified as child?
1) Born at gestational age <38 weeks
2) 0-4 weeks postnatal age
3) 1 month to 2 years of age (1 month to <12 months old)
4) 2-12 years of age (1-12 years old)
5) 12-21 years of age (13-16, 18 or 19 years old)