**Core Concept**
Diphyllobothrium latum, also known as the fish or broad tapeworm, is a large intestinal parasite that infects humans through the consumption of contaminated raw or undercooked fish. The treatment of choice for this parasite involves the use of anthelmintic medications that target its life cycle and prevent re-infection.

**Why the Correct Answer is Right**
The drug of choice for diphyllobothrium latum is niclosamide. It is a benzene carboxamide derivative that acts by inhibiting oxidative phosphorylation in the parasite's mitochondria, ultimately leading to its death. Niclosamide is effective against the adult form of the parasite and is the preferred treatment due to its efficacy and safety profile.

**Why Each Wrong Option is Incorrect**
**Option A:** Praziquantel is a broad-spectrum anthelmintic that is effective against a wide range of parasites, but it is not the first-line treatment for diphyllobothrium latum. It is often used to treat other types of tapeworm infections.
**Option B:** Albendazole is a benzimidazole derivative that is effective against many types of parasites, but it is not the preferred treatment for diphyllobothrium latum. It may be used in combination with other medications for certain types of tapeworm infections.
**Option C:** Praziquantel and albendazole are both effective against certain types of tapeworm infections, but they are not the first-line treatments for diphyllobothrium latum.

**Clinical Pearl / High-Yield Fact**
It's worth noting that re-infection with diphyllobothrium latum can occur if the infected fish is consumed again, so it's essential to cook fish thoroughly before consumption to prevent re-infection.

**Correct Answer: C. Praziquantel**