Ans. C: Metformin Metformin is an oral anti-diabetic drug in the biguanide class. It is the first-line drug of choice for the treatment of type 2 diabetes, paicularly in overweight and obese people and those with normal kidney function When prescribed appropriately, metformin causes few adverse effects--the most common is gastrointestinal upset -- and, unlike many other anti-diabetic drugs, does not cause hypoglycemia if used alone. Lactic acidosis can be a serious concern in overdose. Metformin helps reduce LDL cholesterol and triglyceride levels and is not associated with weight gain, and is the only anti-diabetic drug that has been conclusively shown to prevent the cardiovascular complications of diabetes.