**Core Concept**
Cryptosporidiosis is an intestinal infection caused by the protozoan parasite Cryptosporidium parvum. The treatment of cryptosporidiosis is focused on relieving symptoms and managing the infection, particularly in immunocompromised patients.

**Why the Correct Answer is Right**
Nitazoxanide is a broad-spectrum antiparasitic medication that is effective against Cryptosporidium parvum. It works by inhibiting the pyruvate:ferredoxin oxidoreductase enzyme, which is crucial for the energy metabolism of the parasite. This leads to the disruption of the parasite's energy production and ultimately, the death of the parasite. Nitazoxanide is particularly useful in immunocompromised patients, such as those with HIV/AIDS, who are at increased risk of developing severe cryptosporidiosis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it is not a commonly used medication for treating cryptosporidiosis.
**Option B:** This option is incorrect as it is not a specific treatment for Cryptosporidium parvum.
**Option C:** This option is incorrect as it is not a recommended treatment for cryptosporidiosis in humans.

**Clinical Pearl / High-Yield Fact**
In immunocompromised patients, cryptosporidiosis can lead to severe diarrhea and weight loss, and may require hospitalization. Nitazoxanide is the primary treatment for cryptosporidiosis in these patients, and it has been shown to be effective in reducing symptoms and improving quality of life.

**Correct Answer:** B. Nitazoxanide