**Core Concept**
Anthrax is a zoonotic disease caused by the bacterium *Bacillus anthracis*, which primarily affects animals but can also infect humans through contact with infected animals or contaminated products. The disease is characterized by its distinctive triad of symptoms: cutaneous, inhalational, and gastrointestinal anthrax.

**Why the Correct Answer is Right**
The correct answer is related to the bacterium's unique characteristics. *Bacillus anthracis* is a gram-positive, rod-shaped bacterium with a distinctive feature: it produces spores that are highly resistant to heat, drying, and chemicals. These spores can survive for decades in the environment and can be easily inhaled, ingested, or come into contact with the skin, leading to infection. The bacterium's spores are also highly virulent and can cause severe disease in humans.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because anthrax is not a viral disease. While some diseases are transmitted through viral vectors, anthrax is caused by a bacterium.

**Option B:** This option is incorrect because the disease is not primarily transmitted through the air. While inhalational anthrax is a possible route of infection, it is not the primary mode of transmission.

**Option C:** This option is incorrect because the bacterium's spores are not highly contagious. While the spores can survive for long periods, they do not easily infect other humans or animals.

**Clinical Pearl / High-Yield Fact**
It's essential to note that anthrax spores can be easily killed with heat, drying, or chemicals, making proper handling and disposal crucial in preventing infection.

**Correct Answer:** Not Provided