**Core Concept**
Praziquantel is a benzimidazole anthelmintic that acts by disrupting the calcium ion influx into the parasite's muscle cells, leading to muscle spasm, paralysis, and ultimately, the expulsion of the parasite from the host.

**Why the Correct Answer is Right**
Praziquantel is specifically used for the treatment of schistosomiasis, a parasitic disease caused by the Schistosoma species of flatworms. The drug works by binding to the voltage-gated calcium channels on the parasite's muscle cells, which results in an influx of calcium ions and subsequent muscle contraction. This leads to the death of the parasite, and its subsequent elimination from the host's body. Praziquantel is effective against both the adult and juvenile stages of the parasite.

**Why Each Wrong Option is Incorrect**
**Option A:** Strongyloidiasis is typically treated with ivermectin or albendazole, not praziquantel. Ivermectin is the preferred treatment for this condition due to its high efficacy and safety profile.
**Option B:** Trichomoniasis is a protozoal infection caused by Trichomonas vaginalis, and is treated with metronidazole or tinidazole, not praziquantel.
**Option D:** Rhinosporidiosis is a chronic fungal infection caused by Rhinosporidium seeberi, and is treated with surgical debridement and/or antifungal medications such as itraconazole, not praziquantel.

**Clinical Pearl / High-Yield Fact**
Praziquantel is also used to treat other types of parasitic infections, including fascioliasis, clonorchiasis, and opisthorchiasis. It is generally well-tolerated, but can cause side effects such as dizziness, headache, and abdominal pain in some patients.

✓ Correct Answer: C. Schistosomiasis