Reiko feels hungry often and tends to overeat as a result. Reiko's physician explained to her that her blood sugar level is currently very high, and this has been known to cause an increase in a particular hormone, which can result in increased appetite and the tendency to overeat. The hormone that appears to be causing Reiko to overeat is called

• A. glucagon.
• B. leptin.
• C. insulin.
• D. glucose.