**Core Concept**
Acute hyperkalemia is a life-threatening condition where the serum potassium level exceeds 6.5 mEq/L, posing a significant risk to cardiac myocytes. The condition requires immediate intervention to prevent cardiac arrhythmias, asystole, and death.

**Why the Correct Answer is Right**
The treatment of choice in acute hyperkalemia is calcium gluconate administration. Calcium ions stabilize the cardiac cell membrane by binding to the voltage-gated sodium channels, reducing the risk of cardiac arrhythmias. This action is particularly important in the initial management of hyperkalemia, as it rapidly reverses the cardiac effects of high potassium levels. Intravenous calcium gluconate should be administered concurrently with other treatments, such as insulin and glucose, to drive potassium into cells.

**Why Each Wrong Option is Incorrect**
* **Option A:** Sodium bicarbonate may be useful in treating hyperkalemia caused by acidosis, but it is not the treatment of choice in acute life-threatening hyperkalemia.
* **Option B:** Hemodialysis is the definitive treatment for hyperkalemia, but it takes time to initiate and is not suitable for immediate use in life-threatening situations.
* **Option D:** Beta-agonists, such as albuterol, can help drive potassium into cells but are not as effective as calcium gluconate in stabilizing cardiac membranes.

**Clinical Pearl / High-Yield Fact**
In the initial management of acute hyperkalemia, administering calcium gluconate should be done concurrently with other treatments, such as insulin and glucose, to drive potassium into cells.

**Correct Answer: C. Calcium gluconate**