## **Core Concept**
The transport medium for *Vibrio cholerae* is crucial for preserving the viability of the organism during transportation from the collection site to the laboratory. *Vibrio cholerae* is a gram-negative, curved rod bacterium that causes cholera. The transport medium must maintain the organism's viability without allowing overgrowth of contaminants.

## **Why the Correct Answer is Right**
The correct answer, **C. Cary Blair medium**, is specifically designed for the transport of *Vibrio cholerae*. Cary Blair medium is a low pH, non-nutritive medium that helps to preserve the viability of *Vibrio cholerae* during transport. It contains ingredients like sodium chloride, sodium thioglycolate, and phosphate buffer, which help maintain the organism's viability without supporting the growth of contaminants.

## **Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it is not specified, making it impossible to evaluate its correctness.
* **Option B:** This option is incorrect because it is not specified, making it impossible to evaluate its correctness.
* **Option D:** This option is incorrect because it is not specified, making it impossible to evaluate its correctness.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that Cary Blair medium is specifically used for the transport of *Vibrio cholerae* and other enteric pathogens. It is essential to use the correct transport medium to ensure the accurate isolation and identification of the causative agent.

## **Correct Answer:** **C. Cary Blair medium**