A nurse is reinforcing teaching with a client who has diabetes mellitus type 1 about sick-day management. Which of the following is the priority action for the nurse to recommend to the client?

A. "Monitor blood glucose levels every 4 hours.": Frequent monitoring (often every 3–4 hours) is important during illness, but it supports decision-making rather than being the single highest priority. B. "Consume 15 grams of carbohydrates every 1 to 2 hours.": This is a treatment for hypoglycemia, not a general sick-day strategy for a type 1 diabetic who may have hyperglycemia or risk of DKA. C. "Take the usual dosage of insulin.": Continuing insulin (even if oral intake is reduced) is essential to prevent ketosis and DKA and is therefore the priority action. D. "Drink 8 ounces of fluid every hour while awake.": Maintaining hydration is important to prevent dehydration and help with glucose control, but it is secondary to continuing insulin dosing.