The parent of a 4 month old infant is concerned because the infant does not yet sit by oneself. What is the nurse's best response?

Choice A rationale Sitting unsupported at 4 months of age is generally too early for a developmental milestone. At four months, infants can usually hold their head steady and may prop themselves up on their hands, but they typically have not yet achieved the necessary trunk stability to sit without full assistance or support. Choice B rationale Most infants achieve the developmental milestone of sitting unsupported, which is a major postural accomplishment, between 6 and 8 months of age. Therefore, a 4 month old infant not yet sitting alone is entirely within the expected range of normal development, and the nurse should provide reassurance to the parent. Choice C rationale Sitting unsupported by 12 months would represent a significant developmental delay. By 12 months, the typical infant is often pulling to stand, cruising, or even taking their first independent steps, having mastered sitting many months prior, usually before the 9 month mark. Choice D rationale While some infants may achieve the ability to sit unsupported by 6 months, stating this as the typical age for all infants is an oversimplification. The developmental window for this skill extends up to 8 months, meaning a child not sitting at 4 months is well within the normal range, making the 8 month age a more accurate reference.