This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
Metformin is NOT effective in lowering of blood sugar level in which of the following patients? 
Select and explain. 
A. Non diabetics, B. Obese diabetics, C. Type 2 diabetics, D. Diabetics not responding to sulfonylureas
A: Non diabetics
Answer: A: Non diabetics 
Explanation: (Ref:KDT 6/e p269) Metformin is the drug of choice for the treatment of obese diabetic patients, as it causes weight loss. It does not cause release of insulin, therefore less chances of hypoglycemia.