## Core Concept
The question revolves around the management of *Corynebacterium diphtheriae* infections, focusing on prevention and treatment strategies. *C. diphtheriae* is a bacterium that causes diphtheria, a serious infection that can affect the mucous membranes of the throat and nose. The core concept here involves understanding the role of antimicrobial therapy and immunization in controlling diphtheria.

## Why the Correct Answer is Right
The correct answer, **D. Antitoxin and antibiotics**, is accurate because the primary treatment for diphtheria involves two main components:
- **Antitoxin**: Diphtheria antitoxin is used to neutralize the toxin produced by *C. diphtheriae*. It is crucial for treating patients with suspected or confirmed diphtheria and can help prevent complications if administered early.
- **Antibiotics**: Antibiotics, such as penicillin or erythromycin, are used to eliminate the bacteria from the throat, thereby reducing the risk of transmission to others and preventing further toxin production.

## Why Each Wrong Option is Incorrect
- **Option A: Antitoxin only**. This option is incorrect because while antitoxin is crucial for neutralizing the toxin, antibiotics are necessary to eradicate the bacteria.
- **Option B: Vaccine only**. This option is incorrect because vaccines are primarily used for prevention and do not treat active infections. Vaccination is essential for preventing diphtheria but does not provide immediate immunity or treatment.
- **Option C: Antibiotics only**. This option is incorrect because, although antibiotics are vital for eliminating the bacteria, they do not neutralize the toxin that has already been produced.

## Clinical Pearl / High-Yield Fact
A critical point to remember is that for individuals who have not been vaccinated or whose vaccination status is uncertain, post-exposure prophylaxis with antibiotics and/or vaccination can prevent the development of diphtheria. Additionally, diphtheria antitoxin is a critical component of treatment and should be administered as soon as possible after diagnosis.

## Correct Answer: D. Antitoxin and antibiotics