A nurse is admitting an unidentified female infant who was brought to the emergency department. Based on the assessment findings, the nurse should estimate the infant's age to be which of the following? (Click on the "Exhibit" button below for additional client information. There are three tabs that contain separate categories of data)

A. 3 months: At 3 months, infants typically have a smaller head circumference, weigh less (around 12–13 lb), have fewer teeth, and have not yet demonstrated standing or significant weight-bearing when held. The developmental milestones observed in this infant exceed those expected at 3 months. B. 6 months: The infant’s weight (14.5 lb), height (24 inches), presence of two lower central incisors, ability to bear weight when held in a standing position, hold a bottle, and exhibit a social smile align with typical developmental milestones for a 6-month-old. Neurologic reflexes such as Moro and tonic neck reflexes usually disappear by this age. C. 9 months: By 9 months, infants are usually able to sit without support, may begin crawling, and have more teeth. The inability to sit unsupported indicates the infant is younger than 9 months. D. 12 months: At 12 months, infants generally are able to stand independently, may begin walking, and have more advanced fine motor skills and additional teeth. The developmental abilities and physical measurements of this infant suggest she is younger than 12 months.