A nurse is phoning a provider to report a client's serum potassium of 6.2 mEq/L (3.5-5 mEq/L). Which of the following medications should the nurse expect the provider to prescribe?

A. Acetylcysteine is used as a mucolytic or antidote for acetaminophen toxicity; it has no effect on serum potassium. B. Sodium polystyrene sulfonate (Kayexalate) is a cation-exchange resin that binds potassium in the intestines, allowing it to be excreted in the stool. This medication is commonly prescribed to treat hyperkalemia and lower elevated potassium levels safely. C. Lactulose is used to treat constipation or hepatic encephalopathy and does not reduce serum potassium. D. Potassium iodide is used for thyroid conditions or as a radioprotective agent, not for treating hyperkalemia, and would not be appropriate in this scenario.