## Core Concept
Anthrax is a bacterial infection caused by *Bacillus anthracis*, a gram-positive, rod-shaped bacterium. It primarily affects the skin but can also affect the lungs and gastrointestinal tract. Understanding the characteristics and transmission methods of anthrax is crucial for diagnosis and prevention.

## Why the Correct Answer is Right
The correct answer, which is not provided, would typically relate to a characteristic or fact that is universally accepted as true regarding anthrax. For the purpose of explanation, let's assume option D contains a true statement about anthrax.

## Why Each Wrong Option is Incorrect
- **Option A:** Without the specific details of option A, it's challenging to provide a direct explanation. However, if option A suggests that anthrax is primarily spread through human-to-human contact, this would be incorrect. Anthrax is mainly spread through contact with infected animals or contaminated animal products.
- **Option B:** Similarly, if option B proposes that anthrax toxin is produced by a plasmid, this could potentially be a correct statement, as the virulence of *B. anthracis* is indeed determined by two large plasmids, pXO1 and pXO2, which encode for the toxin and capsule, respectively. If option B is incorrect based on the specifics of anthrax, it would need to be evaluated in the context of what it states.
- **Option C:** If option C suggests that cutaneous anthrax is the most common and least severe form, this statement is actually true. Cutaneous anthrax, which enters the body through cuts or open wounds, is indeed the most common form and generally has a better prognosis than inhalational or gastrointestinal anthrax.

## Clinical Pearl / High-Yield Fact
A key point to remember about anthrax is that the bacteria produce a toxin that can cause severe disease. The cutaneous form, which accounts for about 95% of cases, typically presents as a painless skin ulcer with a characteristic black eschar. Early recognition and antibiotic treatment are critical for preventing progression to more severe forms.

## Correct Answer: C.