Final answer:
C. Prednisone
Rationale: Medications that increase plasma glucose levels are contraindicated for this client.
Corticosteroids, such as prednisone, increase plasma levels of glucose levels and cause
hyperglycemia and glycosuria. Prednisone is contraindicated for a client with type 2 diabetes who takes metformin due to its effect on blood glucose levels.
Step-by-step explanation:
The medication that is contraindicated for a client with type 2 diabetes who takes metformin is Prednisone. Prednisone is a corticosteroid that increases plasma glucose levels, causing hyperglycemia and glycosuria. This medication should be avoided in diabetic clients as it can worsen their blood glucose control.