A 74-year-old woman with chronic kidney disease presents with muscle weakness. Her ECG shows tall peaked T waves and widened QRS complexes. Blood tests confirm a serum potassium of 7.0 mmol/L. What is the most appropriate immediate treatment?AIntravenous calcium gluconate 10 mL of 10% solution over 5–10 minutesBIntravenous 5% dextrose aloneCOral sodium polystyrene sulfonate (calcium resonium)DOral loop diuretic therapy with FrusemideECommence haemodialysis without any other measuresCheck my answer