A nurse is reinforcing teaching with a client who has type 1 diabetes mellitus about self-care during illness. Which of the following instructions should the nurse include in the teaching?

A. "Report a blood glucose level greater than 300.": Persistent hyperglycemia above this threshold (often accompanied by ketones) may signal the need for medical evaluation and possible adjustment of therapy during illness. B. "Test your blood glucose level every 6 hours.": During illness blood glucose monitoring is generally more frequent (for example every 3–4 hours) to detect rapid changes and guide treatment. C. "Administer your usual daily dose of insulin.": Insulin should not be withheld during illness; however dosing may need adjustment based on more frequent glucose checks and oral intake - continuation of baseline insulin is emphasized but individualized. D. "Limit juices, soda, and gelatin.": When at risk of hypoglycemia or unable to eat normally, easily absorbed carbohydrate-containing fluids (juice, soda) are often recommended to treat low blood glucose; blanket restriction of these during illness is not standard sick-day teaching.