**Core Concept**
Woolsorter's disease, also known as anthrax, is a zoonotic disease caused by the bacterium *Bacillus anthracis*. It is characterized by a triad of symptoms: a cutaneous lesion, systemic toxemia, and a severe respiratory illness.

**Why the Correct Answer is Right**
Woolsorter's disease occurs when *B. anthracis* spores are inhaled, leading to the production of anthrax toxins, including lethal factor, edema factor, and protective antigen. These toxins cause the symptoms and complications associated with the disease. The disease was historically common among people who handled infected animal products, such as wool sorters.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Woolsorter's disease is not caused by a viral infection.
**Option B:** This option is incorrect because Woolsorter's disease is not a fungal infection.
**Option C:** This option is incorrect because Woolsorter's disease is not a bacterial infection caused by *Staphylococcus aureus*.

**Clinical Pearl / High-Yield Fact**
Woolsorter's disease is highly infectious and can be transmitted through skin contact with infected animals or contaminated animal products. It is also associated with a characteristic black scab on the skin.

**Correct Answer: C. Cutaneous anthrax is caused by the bacterium Bacillus anthracis.**