## Core Concept
The question revolves around the immediate management of an infant presenting with tetany, which is a condition characterized by muscle cramps, spasms, or tremors, often due to hypocalcemia (low calcium levels). The treatment aims to rapidly correct the underlying cause, typically hypocalcemia.

## Why the Correct Answer is Right
The correct answer involves administering **calcium gluconate**. Tetany in infants is commonly caused by hypocalcemia. Calcium gluconate is a form of calcium replacement that is often used in the treatment of acute hypocalcemia. It works by rapidly increasing serum calcium levels, thereby alleviating the symptoms of tetany. The dosage for infants can vary, but a common approach is to use 100-200 mg/kg of elemental calcium over 5-10 minutes, which can be achieved with calcium gluconate.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is blank and does not provide a viable treatment choice.
- **Option B:** Similarly, this option is blank and does not offer a valid treatment for tetany.
- **Option D:** This option is also blank and lacks a treatment alternative.

## Clinical Pearl / High-Yield Fact
A key point to remember is that in the setting of tetany, especially in infants, it's crucial to quickly assess and treat for hypocalcemia. **Calcium gluconate** is a first-line treatment for acute symptomatic hypocalcemia. Always consider the cause of tetany, as management may vary if it's not due to hypocalcemia.

## Correct Answer Line
**Correct Answer: C. calcium gluconate.**