22. A 6-year-old boy is brought to the clinic by his parents due to concerns about his social interactions and communication skills. His parents report that he rarely makes eye contact, does not respond to his name, and has difficulty engaging in pretend play. He often repeats phrases he hears on YouTube and becomes upset when his daily routine is disrupted. He has a strong interest in trains and can spend hours lining them up in a specific order. His speech is delayed, and he struggles to express his needs or emotions. His teachers have noted that he prefers to play alone and does not interact with other children. There is no history of hearing loss or neurological injury. His developmental milestones were delayed, particularly in language and social skills. Which of the following is the most likely diagnosis? a) Intellectual developmental disorder b) Autism spectrum disorder c) Borderline personality disorder d) Attention deficit hyperactivity disorder (ADHD)