What is the age range defined for infancy in developmental stages?

Infancy is generally defined as the period from birth to around one year of age, but the most widely accepted age range for infancy in developmental stages is from 0 to 1 year. However, the closest choice among the options is the range that includes the entire first three years of life, which encompasses infancy and moves into early childhood.

In this context, the age range from 0 to 3 years aligns more closely with the developmental stages that include significant growth and developmental milestones, such as motor skills, language acquisition, and social interactions. This period represents a critical phase in human development, where foundational skills and behaviors are established. Since the other choices represent narrower stages that do not encompass the full infancy period, the broader range aligns best with standard developmental definitions and observations in early childhood development.