On the basis of the information provided, what is the most likely developmental status of a 4-year-old boy who uses two words spontaneously and functionally, began walking at age 3, and responds inconsistently to his name?

• A. Autism spectrum disorder
• B. Chromosomal anomaly
• C. Developmental delay
• D. Metabolic disorder

Answer: (C)

Understanding developmental milestones helps explain why this picture fits a developmental delay. By age four, children typically use an expressive vocabulary well beyond two words and have already achieved walking long before age two. This child, however, speaks only two words spontaneously and began walking at age three, indicating significant lag in both language and motor development. When milestones in multiple domains are delayed, the label that best fits is developmental delay, reflecting a slower overall pace of development rather than a disorder confined to a single area.

Autism spectrum disorder involves persistent challenges in social communication and interaction, along with restricted, repetitive behaviors; while language delay can appear in autism, the described pattern here centers on broad delay across milestones rather than a specific social-communication profile, making developmental delay the more fitting classification. A chromosomal anomaly or metabolic disorder would usually present with additional signs or systemic problems beyond language and motor delays, which are not described in this scenario.