At what age should a child first be able to sit without support?

A child typically develops the ability to sit without support around the age of 6 months. This milestone indicates a significant level of physical development, as it requires the coordination of muscles in the back and neck to maintain an upright position.

By 6 months, most infants have gained sufficient head and upper body control, allowing them to sit upright for brief periods. This achievement is crucial not only for gross motor skills but also for further development, as sitting allows children to explore their environment more effectively and engage with their caregivers and toys.

In contrast, children may start to show signs of sitting with assistance around 4 months, but they do not have the muscle strength and balance necessary to do so independently. By 9 months, most children are more adept at sitting and may begin to transition to crawling, while at 1 year, children have likely mastered sitting and may be standing or walking. Thus, the milestone of sitting independently is expected first around the 6-month mark, making this the correct answer.