Which Instruction Is Most Important for the Nurse to Teach

Which instruction is most important for the nurse to teach a patient with diabetes who is receiving metformin?

A) Take the medication before meals.
B) This medication will cause the pancreas to secrete more insulin.
C) Stop taking the drug 24 to 48 hours prior to radiopaque dye procedures.
D) There may be an increase in the triglyceride level.