A 64-year-old woman presents with serum potassium 6.8 mmol/L, creatinine 320 µmol/L, peaked T waves on ECG, and mild weakness. According to Canadian nephrology and emergency practice, what is the most urgent initial treatment?AAdminister oral sodium polystyrene sulfonate onlyBGive intravenous calcium gluconate to stabilise the myocardiumCStart an intravenous insulin and dextrose infusion without cardiac monitoringDEncourage high-potassium diet to normalise levelsENo treatment is needed until potassium exceeds 7.5 mmol/LCheck my answer