You are a nurse working on a Medical Unit in a large city hospital. Today you are working a 12-hour shift. It is 9 AM.You receive report on Susan, an 18-year-old college student, who is being transferred from the Intensive Care Unit (ICU).
Susan has type 1 diabetes and was admitted 36 hours ago through the Emergency Department (ED) in diabetic ketoacidosis (DKA), confused and lethargic. She was brought in by her roommate, who reported that Susan had been taking her insulin but hadn't looked good or felt well for a few days. She had been studying very hard for exams.
On the Medical Unit you care for many clients with diabetes. Diabetes is a metabolic disorder characterized by elevated blood glucose (hyperglycemia).
In a person without diabetes, glucose levels are maintained within the normal range through the action of hormones secreted by the pancreas. One of these hormones enables the transport of glucose into cells to be used for energy. This hormone is:

A. insulin
B. pancreatin
C. bile
D. glucagon