A 16-month-old boy is brought to the pediatric clinic by his mother for a well-child visit. She expresses concern that he did not walk independently until 14 months of age, noting that his older sister walked at 10 months. The mother is worried he may have a developmental delay. Vital signs are within normal limits. Physical examination reveals normal strength and tone in bilateral lower extremities, intact deep tendon reflexes, normal gait mechanics, and age-appropriate cognitive and language skills. The child plays appropriately with toys and follows simple commands. Which of the following is the most appropriate next step in management?

1. A)Order neuroimaging (MRI brain) to evaluate for occult central nervous system pathology
2. B)Reassure the mother that the child's development is within normal limits and continues routine preventive careGABARITO
3. C)Refer to pediatric neurology for evaluation of possible cerebral palsy
4. D)Refer to developmental psychology to screen for autism spectrum disorder
5. E)Initiate physical therapy for delayed gross motor development