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?

A. Testing urine for ketones is crucial during illness because it helps in early detection of diabetic ketoacidosis, which can be life-threatening. B. Withholding insulin is dangerous during illness, as the body may require more insulin, not less. C. While it is important to notify the provider if blood glucose levels are elevated, monitoring for ketones takes precedence to prevent complications. D. Limiting fluid intake is not recommended, as fluids are essential for maintaining hydration and helping to manage blood glucose levels during illness.