During his annual physical examination,a 55-year-old man is noted to have a body mass index of 33 (>30 indicates obesity)and high blood pressure.His blood chemistry profile indicates hyperlipidemia,hypertriglyceridemia,and hypercholesterolemia.Furthermore,his fasting blood glucose level is 120 mg/dL (elevated).His physician suspects type 2 diabetes and orders a glucose tolerance test.The patient drinks 75 g of glucose and then has his blood glucose measured 2 hours later.The 2-hour glucose level is 190 mg/dL (high end of glucose intolerance range; for the diagnosis of diabetes,the level is 200 mg/dL or higher).The most likely reason for this patient's glucose intolerance is:
A)Autoimmune destruction of the β cells. B)Impairment of adenosine triphosphate (ATP)-sensitive potassium channel. C)Insulin resistance. D)Low leptin levels. E)Impairment of glucose transporter 2 (GLUT-2)function.