A 7-year-old child is brought by his mother for a school physical. His growth parameters show his height to be 50th percentile and his weight to be significantly higher than 95th percentile. His mother complains that he always seems sleepy during the day and that he has started complaining of headaches. His second-grade teacher has commented that he has difficulty staying awake in class. His mother complains that he wakes up the whole house with his snoring at night. Which of the following is the most appropriate next step in evaluating and managing this condition?
a) Polysomnography
b) Chest x-ray
c) Allergy testing
d) Nasal endoscopy