## Core Concept
The question tests knowledge of specific formulations of medications, focusing on their availability in intravenous (IV) form. This requires understanding of pharmacology and drug formulations.

## Why the Correct Answer is Right
The correct answer, , is only available in intravenous form. This is because it is a medication that requires immediate effect and/or is not absorbed well orally, necessitating the intravenous route for administration.

## Why Each Wrong Option is Incorrect
* **Option A:** is available in oral and possibly other forms, not just IV.
* **Option B:** comes in various formulations, including oral, which makes it incorrect.
* **Option C:** is available in forms other than IV, such as oral or topical, depending on its use.

## Clinical Pearl / High-Yield Fact
A key point to remember is that certain medications are exclusively given intravenously due to their pharmacokinetic properties, such as a very short half-life or poor bioavailability when given orally.

## Correct Answer: D.