This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
[{'content': 'All are ADRs of metformin except \nSelect and explain. \nA. Diarrhoea, B. Wt gain, C. Nausea, D. Lactic acidosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Metformin produces mild weight loss as it causes insulin sensitization and increases glucose uptake into skeletal muscles.Hence considered as drug of choice for patients who are obese and with DM. Ref: KD Tripathi 8th ed.', 'role': 'assistant'}]