A 36-month-old presents for a well child visit. The parents would like to know if the child's development is progressing appropriately. The child passed a hearing test at birth, and other than a few URIs, has been generally healthy. The child has not had any hospitalizations or serious illnesses. The child is able to run well, walk up stairs, walk slowly down stairs, uses more words than the parents are able to count, but can only use them in short, two or three-word sentences. The child's speech is understandable and the child can draw a circle, but not a cross. Neurological examination reveals normal cranial nerves, normal sensitivity, normal motor reflexes, and no Babinski sign. Which of the following is the next best step in management of this child?
A. Perform a brain-stem auditory evoked potential hearing screen
B. Perform a screening exam for autism
C. Reassure the parents that the boy's development appears normal
D. Refer the child to a developmental specialist for comprehensive evaluation
E. Refer the child to a specialist for evaluation of his delayed motor development