A nurse is reinforcing teaching to a client who has diabetes mellitus and is starting oral Metformin to manage blood sugar levels. The nurse should teach the client to avoid consumption of which of the following while taking this medication?

A. Grapefruit does not have a significant interaction with metformin and is generally considered safe in moderation. B. Alcohol should be avoided while taking metformin because it increases the risk of lactic acidosis, a rare but serious complication. C. Milk does not interact adversely with metformin; consuming dairy products is generally safe. D. Shellfish is not contraindicated with metformin and does not affect the medication’s efficacy or safety.