Gian's parents have noted that he seems to have a hard time socially relating to his peers as he cannot seem to understand other people's perspectives. Gian fails to make eye contact during conversation and very poorly responds to changes to routine. Which of the following might his parents be concerned about? A. Attention deficit hyperactivity disorder
B. Tourette's disorder
C. Specific learning disability
D. Autism spectrum disorder
E. Intellectual disability