the correct answer to your question is going to be option a, b, and c. doctors must check the baby's weight, length, and head circumference from birth to 36 months in order to make sure the baby is growing right on track for their age. doctors will measure a baby's weight to make sure they aren't over or under their needed weight, and doctors will check the baby's length to make sure they aren't growing too fast or too slow. they will also check the child's head circumference to make sure that their head size matches the size of their brain for their age. doctors must check these things for baby's this age because if they are not on the correct spot they need to be at for their age, it can be a sign of larger health problems.
let me know if you have any further questions
:)