Which of the following patients is at the highest risk for hyperosmolar hyperglycemic syndrome?

A. A 75-year-old man with type 2 diabetes and coronary artery disease who has recently started on insulin injections: Starting insulin may improve glycemic control, but it does not directly increase the risk for hyperosmolar hyperglycemic syndrome (HHS). HHS usually develops in the context of uncontrolled hyperglycemia rather than new insulin therapy. B. A 45-year-old woman with type 1 diabetes who forgets to take her insulin in the morning: Missing insulin doses in type 1 diabetes is more likely to precipitate diabetic ketoacidosis (DKA) rather than HHS. DKA develops rapidly with ketone formation due to absolute insulin deficiency. C. A 83-year-old long-term care resident with type 2 diabetes and advanced Alzheimer's disease who recently developed influenza: HHS typically occurs in older adults with type 2 diabetes during periods of acute illness or stress, which can cause severe hyperglycemia, dehydration, and hyperosmolarity without significant ketosis. Infection such as influenza increases risk, making this patient the highest risk. D. An 18-year-old college student with type 1 diabetes who exercises excessively: Excessive exercise may affect blood glucose levels but is more likely to cause hypoglycemia in type 1 diabetes rather than precipitate HHS, which occurs mainly in type 2 diabetes under stress or illness.