A nurse is teaching a school-age child who has type 1 diabetes mellitus and his parents about illness management. Which of the following instructions should the nurse include?

Rationale: A. Fluid intake should not be limited during illness; adequate hydration is important to prevent dehydration and complications. B. The provider should be notified if blood glucose levels are consistently elevated or if ketones are present, but the typical threshold for concern is over 240 mg/dL, not 350 mg/dL. C. Insulin should not be withheld during illness; blood glucose may actually rise, and insulin is necessary even if the child is nauseous. D. Testing urine for ketones during illness helps identify early diabetic ketoacidosis, allowing for timely intervention.