A patient with hyperkalemia (K+ 7.5 mEq/L) presents with tall peaked T waves on ECG. Immediate treatment includes:

Correct option is A

In severe hyperkalemia with ECG changes, first step is IV calcium gluconate for cardioprotection. It stabilizes cardiac membranes before shifting or removing potassium.
Explanation of options: (a) ✔ Correct; calcium gluconate prevents arrhythmias immediately. (b) ✘ Insulin + glucose shift K+ intracellularly but act slower; used after stabilization. (c) ✘ Sodium bicarbonate helps in acidosis, less effective acutely. (d) ✘ Hemodialysis is definitive but takes time, not immediate emergency step.